mMDT5_GreenWatch/app/src/main/res/layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="5dp"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/tvMainActivityDeviceListRecyclerView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="@style/TextAppearance.AppCompat.Large"
        android:text="Registered Devices">
    </TextView>

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/deviceListRecyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="3"
        tools:listitem="@layout/device_item">
    </androidx.recyclerview.widget.RecyclerView>

    <TextView
        android:id="@+id/tvMainActivityAlarmHistoryListRecyclerView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="@style/TextAppearance.AppCompat.Large"
        android:text="Alarm History List">
    </TextView>

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/alarmHistoryListRecyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="3"
        tools:listitem="@layout/alarm_history_item">
    </androidx.recyclerview.widget.RecyclerView>

    <SurfaceView
        android:id="@+id/surfaceViewMainActivity"
        android:layout_width="1dp"
        android:layout_height="1dp">
    </SurfaceView>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:layout_weight="3">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal"
            android:layout_weight="1">

            <Button
                android:id="@+id/audiodetectionButton"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginEnd="2dp"
                android:layout_gravity="center_vertical"
                android:layout_weight="1"
                android:text="Audiodetection">
            </Button>

            <Button
                android:id="@+id/videodetectionButton"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginStart="2dp"
                android:layout_gravity="center_vertical"
                android:layout_weight="1"
                android:text="Videodetection">
            </Button>

        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal"
            android:layout_weight="1">

            <Button
                android:id="@+id/accelerometerButton"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_gravity="center_vertical"
                android:layout_weight="1"
                android:text="Accelerometer">
            </Button>

        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal"
            android:layout_weight="1">

            <Button
                android:id="@+id/audiodetectionAndAccelerometerButton"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginEnd="2dp"
                android:layout_gravity="center_vertical"
                android:layout_weight="1"
                android:text="Audiodetection + Accelerometer">
            </Button>

            <Button
                android:id="@+id/videodetectionAndAccelerometerButton"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginStart="2dp"
                android:layout_gravity="center_vertical"
                android:layout_weight="1"
                android:text="Videodetection + Accelerometer">
            </Button>

        </LinearLayout>

    </LinearLayout>

</LinearLayout>