init

.gitignore

@@ -0,0 +1,14 @@
+*.iml
+.gradle
+/local.properties
+/.idea/caches
+/.idea/libraries
+/.idea/modules.xml
+/.idea/workspace.xml
+/.idea/navEditor.xml
+/.idea/assetWizardSettings.xml
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx

.idea/codeStyles/Project.xml

@@ -0,0 +1,116 @@
+<component name="ProjectCodeStyleConfiguration">
+  <code_scheme name="Project" version="173">
+    <codeStyleSettings language="XML">
+      <indentOptions>
+        <option name="CONTINUATION_INDENT_SIZE" value="4" />
+      </indentOptions>
+      <arrangement>
+        <rules>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>xmlns:android</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>xmlns:.*</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*:id</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*:name</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>name</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>style</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>ANDROID_ATTRIBUTE_ORDER</order>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>.*</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
+            </rule>
+          </section>
+        </rules>
+      </arrangement>
+    </codeStyleSettings>
+  </code_scheme>
+</component>

.idea/gradle.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="GradleSettings">
+    <option name="linkedExternalProjectsSettings">
+      <GradleProjectSettings>
+        <option name="testRunner" value="PLATFORM" />
+        <option name="distributionType" value="DEFAULT_WRAPPED" />
+        <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="modules">
+          <set>
+            <option value="$PROJECT_DIR$" />
+            <option value="$PROJECT_DIR$/app" />
+          </set>
+        </option>
+        <option name="resolveModulePerSourceSet" value="false" />
+      </GradleProjectSettings>
+    </option>
+  </component>
+</project>

.idea/misc.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/build/classes" />
+  </component>
+  <component name="ProjectType">
+    <option name="id" value="Android" />
+  </component>
+</project>

.idea/runConfigurations.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RunConfigurationProducerService">
+    <option name="ignoredProducers">
+      <set>
+        <option value="org.jetbrains.plugins.gradle.execution.test.runner.AllInPackageGradleConfigurationProducer" />
+        <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestClassGradleConfigurationProducer" />
+        <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestMethodGradleConfigurationProducer" />
+      </set>
+    </option>
+  </component>
+</project>

app/.gitignore

@@ -0,0 +1 @@
+/build

app/build.gradle

@@ -0,0 +1,34 @@
+apply plugin: 'com.android.application'
+
+android {
+    compileSdkVersion 29
+    buildToolsVersion "29.0.3"
+
+    defaultConfig {
+        applicationId "com.feemers.android.fftdrawer"
+        minSdkVersion 16
+        targetSdkVersion 29
+        versionCode 1
+        versionName "1.0"
+
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+
+}
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+
+    implementation 'androidx.appcompat:appcompat:1.1.0'
+    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
+    testImplementation 'junit:junit:4.12'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+}

app/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

app/src/androidTest/java/com/feemers/android/fftdrawer/ExampleInstrumentedTest.java

@@ -0,0 +1,27 @@
+package com.feemers.android.fftdrawer;
+
+import android.content.Context;
+
+import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static org.junit.Assert.*;
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * @see <a href="http://d.android.com/tools/testing">Testing documentation</a>
+ */
+@RunWith(AndroidJUnit4.class)
+public class ExampleInstrumentedTest {
+    @Test
+    public void useAppContext() {
+        // Context of the app under test.
+        Context appContext = InstrumentationRegistry.getInstrumentation().getTargetContext();
+
+        assertEquals("com.feemers.android.fftdrawer", appContext.getPackageName());
+    }
+}

app/src/main/AndroidManifest.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.feemers.android.fftdrawer">
+
+    <application
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/AppTheme">
+        <activity android:name=".MainActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

app/src/main/java/com/feemers/android/fftdrawer/Animation.java

@@ -0,0 +1,8 @@
+package com.feemers.android.fftdrawer;
+
+import android.graphics.Canvas;
+
+public interface Animation {
+    void Draw(Canvas canvas);
+    void SetBackgroundColor(int c);
+}

app/src/main/java/com/feemers/android/fftdrawer/Bar.java

@@ -0,0 +1,28 @@
+package com.feemers.android.fftdrawer;
+
+import android.graphics.Color;
+
+public class Bar {
+    private float value;
+    private int harmonics;
+    private float frequency;
+    private final int color;
+
+    public Bar(float value, int harmonics) {
+        this.value = value;
+        this.harmonics = harmonics;
+        color = Color.rgb(0,255,0);
+    }
+
+    public float getValue(){
+        return value;
+    }
+
+    public int getHarmonics() {
+        return harmonics;
+    }
+
+    public int getColor(){
+        return color;
+    }
+}

app/src/main/java/com/feemers/android/fftdrawer/BarChart.java

@@ -0,0 +1,62 @@
+package com.feemers.android.fftdrawer;
+
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.Paint;
+
+import java.util.ArrayList;
+
+public class BarChart implements Animation {
+
+    private final int length;
+    private ArrayList<Bar> bars = null;
+
+    private Paint paint;
+    private int backgroundColor;
+
+    public BarChart(int length){
+        this.length = length;
+        bars = new ArrayList<>();
+
+        paint = new Paint();
+        paint.setAntiAlias(true);
+        backgroundColor = Color.rgb(0,0,0);
+    }
+
+    public void newValues(double[] values){
+        bars.clear();
+        for(int i = 0; i < length; i++){
+            float tmp = (float) values[i];
+            bars.add(new Bar(tmp, i));
+        }
+    }
+
+    @Override
+    public void Draw(Canvas canvas) {
+        paint.setStyle(Paint.Style.FILL);
+        canvas.drawColor(backgroundColor);
+        // find max
+        float maxValue = 0;
+        for(Bar b : bars){
+            maxValue = maxValue >= b.getValue() ? maxValue : b.getValue();
+        }
+        for(Bar b : bars){
+            paint.setColor(b.getColor());
+            float width = canvas.getWidth();
+            float heigth = canvas.getHeight();
+            float widthOfBar = width / length;
+
+            float left= b.getHarmonics() * widthOfBar;
+            float top = heigth - heigth * b.getValue() / maxValue;
+            float rigth = (b.getHarmonics()+1) * widthOfBar;
+            float buttom = heigth;
+
+            canvas.drawRect(left, top, rigth ,buttom, paint);
+        }
+    }
+
+    @Override
+    public void SetBackgroundColor(int c) {
+        backgroundColor = c;
+    }
+}

app/src/main/java/com/feemers/android/fftdrawer/BarChartView.java

@@ -0,0 +1,94 @@
+package com.feemers.android.fftdrawer;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.view.SurfaceHolder;
+import android.view.SurfaceView;
+
+public class BarChartView extends SurfaceView implements Runnable {
+
+    private Animation animation;
+    private SurfaceHolder surfaceHolder;
+    private Thread thread = null;
+    private volatile boolean running = false;
+    private int backgroudColor = 0;
+    private String name = "";
+    private int sleepTime = 0;
+    private volatile boolean update;
+
+
+    public BarChartView(Context context) {
+        super(context);
+        surfaceHolder = getHolder();
+    }
+    public BarChartView(Context context, AttributeSet attributeSet){
+        super(context, attributeSet);
+        surfaceHolder = getHolder();
+        ReadXML(attributeSet);
+    }
+    private void ReadXML(AttributeSet attributeSet){
+        android.content.res.TypedArray typedArray = getContext().obtainStyledAttributes(attributeSet, R.styleable.BarChartView);
+        //String s = typedArray.getString(R.styleable.GrafikView_android_text);
+        //name = (s!=null) ? s : "";
+        backgroudColor = typedArray.getColor(R.styleable.BarChartView_backgroundColor, Color.BLACK);
+        typedArray.recycle();
+        log(", hintergrundFarbe=" + backgroudColor);
+    }
+
+    public void setAnimation(Animation animation){
+        this.animation = animation;
+        this.animation.SetBackgroundColor(backgroudColor);
+    }
+
+    private void log(String s) {
+        Log.d(this.getClass().getSimpleName(), s);
+    }
+
+    public void Start(){
+        running = true;
+        thread = new Thread(this);
+        thread.start();
+        log("Thread started");
+    }
+
+    public void Stop(){
+        running = false;
+        while(true){
+            try{
+                thread.join();
+                log("Thread stopped");
+                break;
+            }catch (InterruptedException e){
+                e.printStackTrace();
+            }
+        }
+    }
+    public void Draw(){
+        update = true;
+    }
+
+    @Override
+    public void run() {
+        while (running) {
+            if (update) {
+                if (!surfaceHolder.getSurface().isValid()) {
+                    continue;
+                }
+                Canvas canvas = surfaceHolder.lockCanvas();
+                if (animation != null) {
+                    animation.Draw(canvas);
+                    update = false;
+                }
+                surfaceHolder.unlockCanvasAndPost(canvas);
+            }
+            try {
+                Thread.sleep(5);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+}

app/src/main/java/com/feemers/android/fftdrawer/MainActivity.java

@@ -0,0 +1,76 @@
+package com.feemers.android.fftdrawer;
+
+import androidx.appcompat.app.AppCompatActivity;
+
+import android.content.Context;
+import android.hardware.SensorManager;
+import android.os.Bundle;
+import android.widget.TextView;
+import android.widget.TimePicker;
+
+import com.feemers.android.fftdrawer.SignalProcessing.DetectorTimedomain;
+import com.feemers.android.fftdrawer.SignalProcessing.Logger;
+import com.feemers.android.fftdrawer.SignalProcessing.SignalProcessingControl;
+
+import java.util.Observable;
+import java.util.Observer;
+
+public class MainActivity extends AppCompatActivity implements Observer {
+    private TextView textView1;
+    private BarChartView grafikView1;
+    private TextView textView2;
+    private BarChartView grafikView2;
+    private SignalProcessingControl signalProcessingControl;
+    private  DetectorTimedomain detectorTimedomain;
+    private SensorManager sensorManager;
+    private BarChart barChart;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+        textView1 = findViewById(R.id.textView1);
+        textView1.setText("Nr.1 ");
+        textView2 = findViewById(R.id.textView2);
+        textView2.setText("Nr. 2");
+
+
+        double[] test = new double[64];
+        for (int i = 0; i < 64; i++){
+            test[i] = 0;
+        }
+
+        barChart = new BarChart(64);
+        barChart.newValues(test);
+
+        grafikView1 = findViewById(R.id.graficView1);
+        grafikView1.setAnimation(barChart);
+        grafikView2 = findViewById(R.id.graficView2);
+        grafikView2.setAnimation(new BarChart(64));
+
+        Logger logger = new Logger(this.getClass().getSimpleName(), "");
+        detectorTimedomain = new DetectorTimedomain(20);
+        detectorTimedomain.setThreshold(12);
+
+        sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
+        signalProcessingControl = new SignalProcessingControl(sensorManager, logger);
+        signalProcessingControl.init();
+
+        signalProcessingControl.getNotifier().addObserver(this);
+        signalProcessingControl.start();
+
+
+        grafikView1.Start();
+        grafikView2.Start();
+
+
+    }
+
+    @Override
+    public void update(Observable o, Object arg) {
+        double[] newData = signalProcessingControl.getNotifier().getData();
+        barChart.newValues(newData);
+        grafikView1.Draw();
+        grafikView2.Draw();
+    }
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/Complex.java

@@ -0,0 +1,148 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+/******************************************************************************
+ *  Compilation:  javac Complex.java
+ *  Execution:    java Complex
+ *
+ *  Data type for complex numbers.
+ *
+ *  The data type is "immutable" so once you create and initialize
+ *  a Complex object, you cannot change it. The "final" keyword
+ *  when declaring re and im enforces this rule, making it a
+ *  compile-time error to change the .re or .im instance variables after
+ *  they've been initialized.
+ *
+ *  % java Complex
+ *  a            = 5.0 + 6.0i
+ *  b            = -3.0 + 4.0i
+ *  Re(a)        = 5.0
+ *  Im(a)        = 6.0
+ *  b + a        = 2.0 + 10.0i
+ *  a - b        = 8.0 + 2.0i
+ *  a * b        = -39.0 + 2.0i
+ *  b * a        = -39.0 + 2.0i
+ *  a / b        = 0.36 - 1.52i
+ *  (a / b) * b  = 5.0 + 6.0i
+ *  conj(a)      = 5.0 - 6.0i
+ *  |a|          = 7.810249675906654
+ *  tan(a)       = -6.685231390246571E-6 + 1.0000103108981198i
+ *
+ ******************************************************************************/
+
+public class Complex {
+    private final double re;   // the real part
+    private final double im;   // the imaginary part
+
+    // create a new object with the given real and imaginary parts
+    public Complex(double real, double imag) {
+        re = real;
+        im = imag;
+    }
+
+    // return a string representation of the invoking Complex object
+    public String toString() {
+        if (im == 0) return re + "";
+        if (re == 0) return im + "i";
+        if (im <  0) return re + " - " + (-im) + "i";
+        return re + " + " + im + "i";
+    }
+
+    // return abs/modulus/magnitude
+    public double abs() {
+        return Math.hypot(re, im);
+    }
+
+    // return angle/phase/argument, normalized to be between -pi and pi
+    public double phase() {
+        return Math.atan2(im, re);
+    }
+
+    // return a new Complex object whose value is (this + b)
+    public Complex plus(Complex b) {
+        Complex a = this;             // invoking object
+        double real = a.re + b.re;
+        double imag = a.im + b.im;
+        return new Complex(real, imag);
+    }
+
+    // return a new Complex object whose value is (this - b)
+    public Complex minus(Complex b) {
+        Complex a = this;
+        double real = a.re - b.re;
+        double imag = a.im - b.im;
+        return new Complex(real, imag);
+    }
+
+    // return a new Complex object whose value is (this * b)
+    public Complex times(Complex b) {
+        Complex a = this;
+        double real = a.re * b.re - a.im * b.im;
+        double imag = a.re * b.im + a.im * b.re;
+        return new Complex(real, imag);
+    }
+
+    // return a new object whose value is (this * alpha)
+    public Complex scale(double alpha) {
+        return new Complex(alpha * re, alpha * im);
+    }
+
+    // return a new Complex object whose value is the conjugate of this
+    public Complex conjugate() {
+        return new Complex(re, -im);
+    }
+
+    // return a new Complex object whose value is the reciprocal of this
+    public Complex reciprocal() {
+        double scale = re*re + im*im;
+        return new Complex(re / scale, -im / scale);
+    }
+
+    // return the real or imaginary part
+    public double re() { return re; }
+    public double im() { return im; }
+
+    // return a / b
+    public Complex divides(Complex b) {
+        Complex a = this;
+        return a.times(b.reciprocal());
+    }
+
+    // return a new Complex object whose value is the complex exponential of this
+    public Complex exp() {
+        return new Complex(Math.exp(re) * Math.cos(im), Math.exp(re) * Math.sin(im));
+    }
+
+    // return a new Complex object whose value is the complex sine of this
+    public Complex sin() {
+        return new Complex(Math.sin(re) * Math.cosh(im), Math.cos(re) * Math.sinh(im));
+    }
+
+    // return a new Complex object whose value is the complex cosine of this
+    public Complex cos() {
+        return new Complex(Math.cos(re) * Math.cosh(im), -Math.sin(re) * Math.sinh(im));
+    }
+
+    // return a new Complex object whose value is the complex tangent of this
+    public Complex tan() {
+        return sin().divides(cos());
+    }
+
+
+
+    // a static version of plus
+    public static Complex plus(Complex a, Complex b) {
+        double real = a.re + b.re;
+        double imag = a.im + b.im;
+        Complex sum = new Complex(real, imag);
+        return sum;
+    }
+
+    // See Section 3.3.
+    public boolean equals(Object x) {
+        if (x == null) return false;
+        if (this.getClass() != x.getClass()) return false;
+        Complex that = (Complex) x;
+        return (this.re == that.re) && (this.im == that.im);
+    }
+
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/DetectorImpl.java

@@ -0,0 +1,46 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+import java.util.ArrayList;
+
+
+public class DetectorImpl implements IDetector {
+    protected ArrayList<Double> m_buffer;
+    protected int m_buffer_SIZE; //TODO: Make this this dependent to the sampleRate
+    protected double m_sampleRate;
+    protected ThresholdCalculator m_thresholdCalculator;
+    protected double m_threshold;
+    protected Notifier m_Notifier;
+
+    public DetectorImpl(int windowSize)
+    {
+        m_buffer = new ArrayList<>();
+        m_buffer_SIZE = 128; //TODO later: Change this hardcoded value and calculate it during runtime -> depending on sampleRate
+        m_sampleRate = 0;
+        m_thresholdCalculator = new ThresholdCalculator(windowSize);
+        m_threshold = m_thresholdCalculator.getThreshold();
+    }
+
+    @Override
+    public void onNewSample(double sample) {
+        m_thresholdCalculator.onNewSample(sample);
+        m_threshold = m_thresholdCalculator.getThreshold();
+    }
+
+    @Override
+    public void setSampleRate(double sampleRate) {
+        m_sampleRate = sampleRate;
+    }
+
+    @Override
+    public void setThreshold(double threshold) {
+        // Call this to set the constant part of the threshold determined by the user
+        m_thresholdCalculator.setConstantThresholdPart(threshold);
+    }
+
+    public void connectNotifier(Notifier notifier){
+        if(notifier == null){
+            throw new AssertionError("Notifier is null");
+        }
+        m_Notifier = notifier;
+    }
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/DetectorTimedomain.java

@@ -0,0 +1,72 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+import android.util.Log;
+import android.util.Pair;
+
+import java.util.ArrayList;
+
+public class DetectorTimedomain extends DetectorImpl {
+    private boolean m_calculate_amplitude;
+    private int m_threshold_cnt;
+    private int m_sample_cnt;
+
+    public DetectorTimedomain(int windowSize) {
+        super(windowSize);
+        Log.d("DetectorTimedomain", "DetectorTimedomain() - Constructor called");
+        m_calculate_amplitude = false;
+        m_threshold_cnt = 0;
+        m_sample_cnt = 0;
+    }
+
+    @Override
+    public void onNewSample(double sample) {
+        super.onNewSample(sample);
+        check_for_earthquake(sample);
+    }
+
+    public void check_for_earthquake(double sample)
+    {
+        // This method checks if threshold was exceeded and calculates the amplitude if enough values are available
+        // Possible combinitions of the return values:
+        // 1: false, 0.0   -> Threshold wasn't exceeded
+        // 2: true, 0.0   -> Threshold was exceeded, but no value for amplitude is available yet (because m_buffer isn't filled yet)
+        // 3: true, amplitude   -> Threshold was exceeded and a value for amplitude is available
+        //TODO: find better solution for returning the results -> temp solution: No return-values but printing to logcat instead. Use Notifier later.
+
+        Pair<Boolean, Double> return_pair = new Pair<Boolean, Double>(false, 0.0);
+        if ((sample > m_threshold) && !(m_calculate_amplitude)) {
+            Log.d("DetectorTimedomain", "threshold was exceeded. threshold: " + m_threshold); //TODO: send this info with notifier instead
+            m_threshold_cnt++;
+            // Later: add Logger entry
+            m_calculate_amplitude = true;
+            m_buffer = new ArrayList<>(); //resetting to an empty ArrayList
+        }
+
+        if (m_calculate_amplitude) {
+            if (m_sample_cnt >= m_buffer_SIZE) {
+                //Vector sensor_samples is filled -> determine amplitude
+                double amplitude = calculate_maximum(m_buffer);
+                m_sample_cnt = 0;
+                m_calculate_amplitude = false;
+                Log.d("DetectorTimedomain", "Maximum calculated: " + amplitude); //TODO: send this message with notifier instead
+                return_pair = new Pair<Boolean, Double>(true, amplitude);
+                // Later: add Logger entry
+            } else {
+                m_buffer.add(sample);
+                m_sample_cnt++;
+                return_pair = new Pair<Boolean, Double>(true, 0.0);
+            }
+        }
+        m_Notifier.sendEvent();
+        //return return_pair;
+    }
+
+    private double calculate_maximum(ArrayList<Double> samples) {
+        double maximum = 0;
+        for (double sample : samples) {
+            if (maximum < sample)
+                maximum = sample;
+        }
+        return maximum;
+    }
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/FFT.java

@@ -0,0 +1,206 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+
+/******************************************************************************
+ *  Compilation:  javac FFT.java
+ *  Execution:    java FFT n
+ *  Dependencies: Complex.java
+ *
+ *  Compute the FFT and inverse FFT of a length n complex sequence
+ *  using the radix 2 Cooley-Tukey algorithm.
+
+ *  Bare bones implementation that runs in O(n log n) time and O(n)
+ *  space. Our goal is to optimize the clarity of the code, rather
+ *  than performance.
+ *
+ *  This implementation uses the primitive root of unity w = e^(-2 pi i / n).
+ *  Some resources use w = e^(2 pi i / n).
+ *
+ *  Reference: https://www.cs.princeton.edu/~wayne/kleinberg-tardos/pdf/05DivideAndConquerII.pdf
+ *
+ *  Limitations
+ *  -----------
+ *   -  assumes n is a power of 2
+ *
+ *   -  not the most memory efficient algorithm (because it uses
+ *      an object type for representing complex numbers and because
+ *      it re-allocates memory for the subarray, instead of doing
+ *      in-place or reusing a single temporary array)
+ *
+ *  For an in-place radix 2 Cooley-Tukey FFT, see
+ *  https://introcs.cs.princeton.edu/java/97data/InplaceFFT.java.html
+ *
+ ******************************************************************************/
+
+public class FFT {
+
+    // compute the FFT of x[], assuming its length n is a power of 2
+    public static Complex[] fft(Complex[] x) {
+        int n = x.length;
+
+        // base case
+        if (n == 1) return new Complex[] { x[0] };
+
+        // radix 2 Cooley-Tukey FFT
+        if (n % 2 != 0) {
+            throw new IllegalArgumentException("n is not a power of 2");
+        }
+
+        // compute FFT of even terms
+        Complex[] even = new Complex[n/2];
+        for (int k = 0; k < n/2; k++) {
+            even[k] = x[2*k];
+        }
+        Complex[] evenFFT = fft(even);
+
+        // compute FFT of odd terms
+        Complex[] odd  = even;  // reuse the array (to avoid n log n space)
+        for (int k = 0; k < n/2; k++) {
+            odd[k] = x[2*k + 1];
+        }
+        Complex[] oddFFT = fft(odd);
+
+        // combine
+        Complex[] y = new Complex[n];
+        for (int k = 0; k < n/2; k++) {
+            double kth = -2 * k * Math.PI / n;
+            Complex wk = new Complex(Math.cos(kth), Math.sin(kth));
+            y[k]       = evenFFT[k].plus (wk.times(oddFFT[k]));
+            y[k + n/2] = evenFFT[k].minus(wk.times(oddFFT[k]));
+        }
+        return y;
+    }
+
+
+    // compute the inverse FFT of x[], assuming its length n is a power of 2
+    public static Complex[] ifft(Complex[] x) {
+        int n = x.length;
+        Complex[] y = new Complex[n];
+
+        // take conjugate
+        for (int i = 0; i < n; i++) {
+            y[i] = x[i].conjugate();
+        }
+
+        // compute forward FFT
+        y = fft(y);
+
+        // take conjugate again
+        for (int i = 0; i < n; i++) {
+            y[i] = y[i].conjugate();
+        }
+
+        // divide by n
+        for (int i = 0; i < n; i++) {
+            y[i] = y[i].scale(1.0 / n);
+        }
+
+        return y;
+
+    }
+
+    // compute the circular convolution of x and y
+    public static Complex[] cconvolve(Complex[] x, Complex[] y) {
+
+        // should probably pad x and y with 0s so that they have same length
+        // and are powers of 2
+        if (x.length != y.length) {
+            throw new IllegalArgumentException("Dimensions don't agree");
+        }
+
+        int n = x.length;
+
+        // compute FFT of each sequence
+        Complex[] a = fft(x);
+        Complex[] b = fft(y);
+
+        // point-wise multiply
+        Complex[] c = new Complex[n];
+        for (int i = 0; i < n; i++) {
+            c[i] = a[i].times(b[i]);
+        }
+
+        // compute inverse FFT
+        return ifft(c);
+    }
+
+
+    // compute the linear convolution of x and y
+    public static Complex[] convolve(Complex[] x, Complex[] y) {
+        Complex ZERO = new Complex(0, 0);
+
+        Complex[] a = new Complex[2*x.length];
+        for (int i = 0;        i <   x.length; i++) a[i] = x[i];
+        for (int i = x.length; i < 2*x.length; i++) a[i] = ZERO;
+
+        Complex[] b = new Complex[2*y.length];
+        for (int i = 0;        i <   y.length; i++) b[i] = y[i];
+        for (int i = y.length; i < 2*y.length; i++) b[i] = ZERO;
+
+        return cconvolve(a, b);
+    }
+
+    // compute the DFT of x[] via brute force (n^2 time)
+    public static Complex[] dft(Complex[] x) {
+        int n = x.length;
+        Complex ZERO = new Complex(0, 0);
+        Complex[] y = new Complex[n];
+        for (int k = 0; k < n; k++) {
+            y[k] = ZERO;
+            for (int j = 0; j < n; j++) {
+                int power = (k * j) % n;
+                double kth = -2 * power *  Math.PI / n;
+                Complex wkj = new Complex(Math.cos(kth), Math.sin(kth));
+                y[k] = y[k].plus(x[j].times(wkj));
+            }
+        }
+        return y;
+    }
+
+
+    /***************************************************************************
+     *  Test client and sample execution
+     *
+     *  % java FFT 4
+     *  x
+     *  -------------------
+     *  -0.03480425839330703
+     *  0.07910192950176387
+     *  0.7233322451735928
+     *  0.1659819820667019
+     *
+     *  y = fft(x)
+     *  -------------------
+     *  0.9336118983487516
+     *  -0.7581365035668999 + 0.08688005256493803i
+     *  0.44344407521182005
+     *  -0.7581365035668999 - 0.08688005256493803i
+     *
+     *  z = ifft(y)
+     *  -------------------
+     *  -0.03480425839330703
+     *  0.07910192950176387 + 2.6599344570851287E-18i
+     *  0.7233322451735928
+     *  0.1659819820667019 - 2.6599344570851287E-18i
+     *
+     *  c = cconvolve(x, x)
+     *  -------------------
+     *  0.5506798633981853
+     *  0.23461407150576394 - 4.033186818023279E-18i
+     *  -0.016542951108772352
+     *  0.10288019294318276 + 4.033186818023279E-18i
+     *
+     *  d = convolve(x, x)
+     *  -------------------
+     *  0.001211336402308083 - 3.122502256758253E-17i
+     *  -0.005506167987577068 - 5.058885073636224E-17i
+     *  -0.044092969479563274 + 2.1934338938072244E-18i
+     *  0.10288019294318276 - 3.6147323062478115E-17i
+     *  0.5494685269958772 + 3.122502256758253E-17i
+     *  0.240120239493341 + 4.655566391833896E-17i
+     *  0.02755001837079092 - 2.1934338938072244E-18i
+     *  4.01805098805014E-17i
+     *
+     ***************************************************************************/
+
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/IDetector.java

@@ -0,0 +1,8 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+public interface IDetector {
+    public void onNewSample(double sample);
+    public void setSampleRate(double sampleRate);
+    public void setThreshold(double threshold);
+    public void connectNotifier(Notifier notifier);
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/ISensor.java

@@ -0,0 +1,11 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+public interface ISensor {
+    public double getSampleRate();
+
+    public void connectDetector(IDetector detector);
+
+    public void startSampling();
+
+    public void stopSampling();
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/Logger.java

@@ -0,0 +1,76 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+import android.app.Activity;
+import android.util.Log;
+import android.widget.TextView;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+public class Logger
+{
+    private TextView textView; 
+    private StringBuffer sb = new StringBuffer(); 
+    private String tag; 
+    private Activity activity; 
+
+    public Logger(String tag, String logInitText)
+    {
+        this.activity = null;
+        this.tag = tag;
+        sb.append(logInitText);
+    }
+
+    public Logger(Activity activity, String tag, TextView textView, String logInitText) 
+    {
+        this.activity = activity;
+        this.tag = tag;
+        this.textView = textView;
+        sb.append(logInitText);
+    }
+
+    public void log(String s) 
+    {
+        Log.d(tag, s);
+        sb.append(s).append("\n");
+        if (textView != null)
+        {
+            if(activity !=null)
+            {
+                activity.runOnUiThread(new Runnable()
+                {
+                    @Override
+                    public void run()
+                    {
+                        textView.setText(sb.toString());
+                    }
+                });
+            }
+            else
+            {
+                textView.setText(sb.toString());
+            }
+        }
+    }
+
+    public void log(Exception e) 
+    {
+        StringWriter sw = new StringWriter();
+        e.printStackTrace(new PrintWriter(sw));
+        log(sw.toString());
+    }
+
+    public void clearLog() 
+    {
+        sb.setLength(0);
+        if (textView != null)
+        {
+            textView.setText("");
+        }
+    }
+
+    public String getLoggedText() 
+    {
+        return sb.toString();
+    }
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/MySensor.java

@@ -0,0 +1,95 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+import android.hardware.Sensor;
+import android.hardware.SensorEvent;
+import android.hardware.SensorEventListener;
+import android.hardware.SensorManager;
+import android.util.Log;
+
+public class  MySensor extends SensorImpl implements SensorEventListener {
+    private SensorManager sensorManager;
+    private Sensor m_sensor;
+    private int sensorType = Sensor.TYPE_ACCELEROMETER;
+    private long time_former_value;
+    private long time_current_value;
+
+    private int sample_cnt;
+
+    public MySensor()
+    {
+        m_sensor = null;
+        time_former_value = 0;
+        time_current_value = 0;
+        sample_cnt = 0;
+    }
+
+    @Override
+    public void onSensorChanged(SensorEvent event)
+    {
+        //Log.d("MySensor","onSensorChanged()\n");
+
+        // Calculating the sample rate
+        time_current_value = System.currentTimeMillis();
+        long period = time_current_value - time_former_value;
+        if ((time_former_value != 0) && (period != 0)) {
+            m_sampleRate = (double) (1.0 / period) * 1000.0; // in Hz
+            m_detector.setSampleRate(m_sampleRate);
+        }
+
+        /*if (sample_cnt == 100) //TODO: Delete this part before final use (inc. sample_cnt) -> only meant for debugging
+        {
+            Log.d("MySensor", "m_sampleRate:" + m_sampleRate + "\n");
+            Log.d("MySensor", "time_current_value:" + time_current_value + "\n");
+            Log.d("MySensor", "time_former_value:" + time_former_value + "\n");
+            Log.d("MySensor", "currentTimeMillis:" + System.currentTimeMillis() + "\n");
+            Log.d("MySensor", "period:" + period + "\n");
+            sample_cnt = 0;
+        }*/
+
+        time_former_value = time_current_value;
+        // Calculating the acceleration
+        double acceleration = (Math.sqrt(event.values[0] * event.values[0] + event.values[1] * (event.values[1] + event.values[2] * event.values[2]))) - 9.81;
+        m_detector.onNewSample(acceleration);
+        sample_cnt++;
+    }
+
+    @Override
+    public void onAccuracyChanged(Sensor sensor, int accuracy) {
+        Log.d("MySensor","onAccuracyChanged()\n");
+    }
+
+    @Override
+    public double getSampleRate() {
+        return m_sampleRate;
+    }
+
+    @Override
+    public void startSampling() {
+        if (m_sensor != null) {
+            if (sensorManager.registerListener(this, m_sensor, SensorManager.SENSOR_DELAY_GAME)) {
+                Log.d("MySensor", "Bei Sensor angemeldet.\n");
+            } else {
+                Log.d("MySensor", "Kann dem Sensor keinen Beobachter hinzufügen\n");
+            }
+        }
+    }
+
+    @Override
+    public void stopSampling() {
+        if (m_sensor != null) {
+            sensorManager.unregisterListener(this, m_sensor);
+            Log.d("MySensor","Von Sensor abgemeldet.\n");
+        }
+    }
+
+
+    public void connectSensorManager(SensorManager sensorManager){
+        this.sensorManager = sensorManager;
+        if (sensorManager.getSensorList(sensorType).size() == 0) {
+            Log.d("MySensor", "Es gibt den Sensor nicht.\n");
+            m_sensor = null;
+        } else {
+            m_sensor = sensorManager.getSensorList(sensorType).get(0);
+        }
+    }
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/Notifier.java

@@ -0,0 +1,26 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+import android.util.Log;
+
+import java.util.Observable;
+
+public class Notifier extends Observable {
+    private double[] data;
+
+    public Notifier(){
+
+    }
+    public void sendEvent(){
+        Log.d("Hi", "sendEvent: Test");
+    }
+
+    public void onNewFFTData(double[] data){
+        this.data = data;
+        setChanged();
+        notifyObservers();
+    }
+
+    public double[] getData() {
+        return data;
+    }
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/SensorFake.java

@@ -0,0 +1,18 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+public class SensorFake extends SensorImpl {
+    @Override
+    public double getSampleRate() {
+        return 0;
+    }
+
+    @Override
+    public void startSampling() {
+
+    }
+
+    @Override
+    public void stopSampling() {
+
+    }
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/SensorImpl.java

@@ -0,0 +1,19 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+public abstract class SensorImpl implements ISensor {
+    protected IDetector m_detector;
+    protected double m_sampleRate;
+
+    public SensorImpl()
+    {
+        m_detector = null;
+        m_sampleRate = 0;
+    }
+
+    public void connectDetector(IDetector detector){
+        if(detector == null){
+            throw new AssertionError("detector == null");
+        }
+        m_detector = detector;
+    }
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/SignalProcessingControl.java

@@ -0,0 +1,51 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+import android.hardware.SensorManager;
+
+import java.util.Observer;
+
+
+public class SignalProcessingControl {
+    private IDetector detector;
+    private ISensor sensor;
+    private Notifier notifier;
+    private Logger logger;
+
+    public SignalProcessingControl(SensorManager sensorManager, Logger logger) {
+        this.logger = logger;
+        logger.log("SignalProcessingControl()");
+
+        // create notifier
+        notifier = new Notifier();
+
+        // create detector
+        //detector = new DetectorTimedomain(20);
+        detector = new DetectorFFT(20);
+        detector.setThreshold(6); //TODO: Remove hardcoded threshold and read from GUI instead
+        detector.connectNotifier(notifier);
+
+        // create & link hardware to sensor -> sensorManager
+        MySensor mySensor = new MySensor();
+        mySensor.connectSensorManager(sensorManager);
+        this.sensor = mySensor;
+    }
+
+    public void init() {
+        logger.log("SignalProcessingControl: init()");
+        sensor.connectDetector(detector);
+    }
+
+    public void start() {
+        logger.log("SignalProcessingControl: start()");
+        sensor.startSampling();
+    }
+
+    public void stop() {
+        logger.log("SignalProcessingControl: stop()");
+        sensor.stopSampling();
+    }
+
+    public Notifier getNotifier() {
+        return notifier;
+    }
+}

app/src/main/java/com/feemers/android/fftdrawer/SignalProcessing/ThresholdCalculator.java

@@ -0,0 +1,67 @@
+package com.feemers.android.fftdrawer.SignalProcessing;
+
+class ThresholdCalculator {
+    private double[] m_buffer;
+    private int m_windowSize;
+    private int m_bufferCounter;
+    private int m_bufferInitCounter;
+    private double m_constantThresholdPart;
+    private double m_adaptiveThresholdPart;
+
+    public ThresholdCalculator(int windowSize) {
+        if (windowSize <= 0) {
+            throw new AssertionError("windowSize should be postive");
+        }
+        m_windowSize = windowSize;
+        reset();
+    }
+
+    public double getThreshold() {
+        // This method is meant for the use inside of a detector implementation
+        // Should be called every time a new sensor value is available
+        // Returns the sum of the constant part of the threshold (determined by the user) and the
+        // adaptive part of the threshold (determined by the noise level of the signal)
+        return m_constantThresholdPart + m_adaptiveThresholdPart;
+    }
+
+    public void setConstantThresholdPart(double constantThresholdPart) {
+        // This method should be called when the User changes the constant part of the threshold with the GUI
+        this.m_constantThresholdPart = constantThresholdPart;
+    }
+
+    public void onNewSample(double sample) {
+        // store sample
+        m_buffer[m_bufferCounter] = sample;
+        // increase counter
+        m_bufferCounter++;
+        // check if we are on the end of Array -> go to start
+        if (m_bufferCounter >= m_windowSize) {
+            m_bufferCounter = 0;
+        }
+
+        // when we start the application we will have an arry with emty values
+        // hence we define how many values are already new
+        // after N_sample == windowSize this will have no further effect
+        if (m_bufferInitCounter < m_windowSize) {
+            m_bufferInitCounter++;
+        }
+
+        // now calculate Mean
+        double absMean = 0;
+        for (int i = 0; i < m_bufferInitCounter; i++) {
+            double sampleVal = m_buffer[i];
+            absMean += Math.sqrt(sampleVal * sampleVal);
+        }
+        m_adaptiveThresholdPart = absMean / m_bufferInitCounter;
+    }
+
+    // for reset this class reset
+    public void reset() {
+        m_bufferCounter = 0;
+        m_bufferInitCounter = 0;
+        m_buffer = new double[m_windowSize];
+        for (int i = 0; i < m_windowSize; i++) {
+            m_buffer[i] = 0;
+        }
+    }
+}

app/src/main/res/drawable-v24/ic_launcher_foreground.xml

@@ -0,0 +1,30 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path android:pathData="M31,63.928c0,0 6.4,-11 12.1,-13.1c7.2,-2.6 26,-1.4 26,-1.4l38.1,38.1L107,108.928l-32,-1L31,63.928z">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:endX="85.84757"
+                android:endY="92.4963"
+                android:startX="42.9492"
+                android:startY="49.59793"
+                android:type="linear">
+                <item
+                    android:color="#44000000"
+                    android:offset="0.0" />
+                <item
+                    android:color="#00000000"
+                    android:offset="1.0" />
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+        android:fillColor="#FFFFFF"
+        android:fillType="nonZero"
+        android:pathData="M65.3,45.828l3.8,-6.6c0.2,-0.4 0.1,-0.9 -0.3,-1.1c-0.4,-0.2 -0.9,-0.1 -1.1,0.3l-3.9,6.7c-6.3,-2.8 -13.4,-2.8 -19.7,0l-3.9,-6.7c-0.2,-0.4 -0.7,-0.5 -1.1,-0.3C38.8,38.328 38.7,38.828 38.9,39.228l3.8,6.6C36.2,49.428 31.7,56.028 31,63.928h46C76.3,56.028 71.8,49.428 65.3,45.828zM43.4,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2c-0.3,-0.7 -0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C45.3,56.528 44.5,57.328 43.4,57.328L43.4,57.328zM64.6,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2s-0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C66.5,56.528 65.6,57.328 64.6,57.328L64.6,57.328z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000" />
+</vector>

app/src/main/res/drawable/ic_launcher_background.xml

@@ -0,0 +1,170 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:fillColor="#3DDC84"
+        android:pathData="M0,0h108v108h-108z" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M9,0L9,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,0L19,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,0L29,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,0L39,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,0L49,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,0L59,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,0L69,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,0L79,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M89,0L89,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M99,0L99,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,9L108,9"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,19L108,19"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,29L108,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,39L108,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,49L108,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,59L108,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,69L108,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,79L108,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,89L108,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,99L108,99"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,29L89,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,39L89,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,49L89,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,59L89,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,69L89,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,79L89,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,19L29,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,19L39,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,19L49,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,19L59,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,19L69,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,19L79,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+</vector>

app/src/main/res/layout/activity_main.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    xmlns:mynamespace="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".MainActivity"
+    android:orientation="vertical"
+    tools:activity=".MainActivity">
+    <TextView
+        android:id="@+id/textView1"
+        android:layout_width="fill_parent"
+        android:layout_height="wrap_content"/>
+
+    <com.feemers.android.fftdrawer.BarChartView
+        android:id="@+id/graficView1"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_weight="2"
+        mynamespace:backgroundColor="#4C614C"/>
+    <TextView
+        android:id="@+id/textView2"
+        android:layout_width="fill_parent"
+        android:layout_height="wrap_content"/>
+
+    <com.feemers.android.fftdrawer.BarChartView
+        android:id="@+id/graficView2"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_weight="2"
+        mynamespace:backgroundColor="#75455E"/>
+</LinearLayout>

app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

app/src/main/res/values/attributes.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <declare-styleable name="BarChartView">
+        <attr name="backgroundColor" format="color"/>
+    </declare-styleable>
+</resources>

app/src/main/res/values/colors.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="colorPrimary">#6200EE</color>
+    <color name="colorPrimaryDark">#3700B3</color>
+    <color name="colorAccent">#03DAC5</color>
+</resources>

app/src/main/res/values/strings.xml

@@ -0,0 +1,3 @@
+<resources>
+    <string name="app_name">FFTDrawer</string>
+</resources>

app/src/main/res/values/styles.xml

@@ -0,0 +1,11 @@
+<resources>
+
+    <!-- Base application theme. -->
+    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
+        <!-- Customize your theme here. -->
+        <item name="colorPrimary">@color/colorPrimary</item>
+        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
+        <item name="colorAccent">@color/colorAccent</item>
+    </style>
+
+</resources>

app/src/test/java/com/feemers/android/fftdrawer/ExampleUnitTest.java

@@ -0,0 +1,17 @@
+package com.feemers.android.fftdrawer;
+
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+/**
+ * Example local unit test, which will execute on the development machine (host).
+ *
+ * @see <a href="http://d.android.com/tools/testing">Testing documentation</a>
+ */
+public class ExampleUnitTest {
+    @Test
+    public void addition_isCorrect() {
+        assertEquals(4, 2 + 2);
+    }
+}

build.gradle

@@ -0,0 +1,29 @@
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+
+buildscript {
+    
+    repositories {
+        google()
+        jcenter()
+        
+    }
+    dependencies {
+        classpath 'com.android.tools.build:gradle:3.6.1'
+        
+
+        // NOTE: Do not place your application dependencies here; they belong
+        // in the individual module build.gradle files
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        jcenter()
+        
+    }
+}
+
+task clean(type: Delete) {
+    delete rootProject.buildDir
+}

gradle.properties

@@ -0,0 +1,20 @@
+# Project-wide Gradle settings.
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+# Specifies the JVM arguments used for the daemon process.
+# The setting is particularly useful for tweaking memory settings.
+org.gradle.jvmargs=-Xmx1536m
+# When configured, Gradle will run in incubating parallel mode.
+# This option should only be used with decoupled projects. More details, visit
+# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
+# org.gradle.parallel=true
+# AndroidX package structure to make it clearer which packages are bundled with the
+# Android operating system, and which are packaged with your app's APK
+# https://developer.android.com/topic/libraries/support-library/androidx-rn
+android.useAndroidX=true
+# Automatically convert third-party libraries to use AndroidX
+android.enableJetifier=true
+

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Mon Jun 08 18:27:45 CEST 2020
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.4-all.zip

gradlew

@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

@@ -0,0 +1,2 @@
+rootProject.name='FFTDrawer'
+include ':app'