Refactored in Main

app/src/main/java/com/example/ueberwachungssystem/MainActivity.java

 public class MainActivity extends AppCompatActivity {
 
     private static final int CAMERA_PERMISSION_REQUEST_CODE = 101;
-    private PreviewView previewView;
-    private TextView textView;
-    private ToggleButton toggleButton;
-    private Boolean cameraPreviewIsRunning = false;
-    private Boolean isPressed = false;
 
 
     @Override
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
 
-        textView = findViewById(R.id.textView);
-        previewView = findViewById(R.id.previewView);
-        toggleButton = findViewById(R.id.previewButton);
+        TextView textView = findViewById(R.id.textView);
+        PreviewView previewView = findViewById(R.id.previewView);
 
 
         VideoDetector vd = new VideoDetector(this);
         vd.setPreviewView(previewView);
         vd.setOnDetectionListener(new VideoDetector.OnDetectionListener() {
             @Override
-            public void onDetection(DetectionReport detectionReport) {
+            public void onDetection(@NonNull DetectionReport detectionReport) {
                 detectionReport.log("OnDetection");
                 textView.setText(detectionReport.toString());
             }
         //vd.startDetection();
 
 
+        ToggleButton toggleButton = findViewById(R.id.previewButton);
         toggleButton.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {