Proximity screen off

We can learn how to screen off with proximity

import android.content.Context;
import android.os.PowerManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private PowerManager mPowerManager;
    private PowerManager.WakeLock mWakeLock;

    private static final String TAG = "MainActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mPowerManager = (PowerManager) getSystemService(Context.POWER_SERVICE);
    }

    public void activateSensor(View v) {
        Toast.makeText(MainActivity.this, "Proximity On", Toast.LENGTH_LONG).show();
        if (mWakeLock == null) {
            mWakeLock = mPowerManager.newWakeLock(PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK, "incall");
        }
        if (!mWakeLock.isHeld()) {
            Log.d(TAG, "New call active : acquiring incall (CPU only) wake lock");
            mWakeLock.acquire();
        } else {
            Log.d(TAG, "New call active while incall (CPU only) wake lock already active");
        }
    }

    public void deactivateSensor(View v) {
        Toast.makeText(MainActivity.this, "Proximity Off", Toast.LENGTH_LONG).show();
        if (mWakeLock != null && mWakeLock.isHeld()) {
            mWakeLock.release();
            Log.d(TAG, "Last call ended: releasing incall (CPU only) wake lock");
        } else {
            Log.d(TAG, "Last call ended: no incall (CPU only) wake lock were held");
        }
    }

}

And now in your layout:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.javier.proximitysensor.MainActivity">

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@+id/activity_main_turn_on_screen"
        android:onClick="activateSensor"
        android:text="@string/activity_main_activate_sensor" />

    <Button
        android:id="@+id/activity_main_turn_on_screen"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:onClick="deactivateSensor"
        android:text="@string/activity_main_deactivate_sensor" />
</RelativeLayout>