UnregisterListener doesn't work with PROXIMITY

Question

I have this code

public class MainActivity extends AppCompatActivity implements SensorEventListener {

    private SensorManager mSensorManager;
    private Sensor mProximity;
    private PowerManager mPowerManager;
    private PowerManager.WakeLock mWakeLock;


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


        mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        mProximity = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);

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

    @Override
    protected void onResume() {
        super.onResume();
        mSensorManager.registerListener(this, mProximity, SensorManager.SENSOR_DELAY_NORMAL);
    }

    @Override
    protected void onPause() {
        super.onPause();
        mSensorManager.unregisterListener(this);
    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        if (event.sensor.getType() == Sensor.TYPE_PROXIMITY) {
            if (event.values[0] == 0) {
                //near
                Toast.makeText(getApplicationContext(), "near", Toast.LENGTH_SHORT).show();
                turnOffScreen();

            } else {
                //far
                Toast.makeText(getApplicationContext(), "far", Toast.LENGTH_SHORT).show();
                turnOnScreen();
            }
        }
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {

    }


    public void turnOffScreen() {

            mWakeLock = mPowerManager.newWakeLock(PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK, "tag");
            mWakeLock.acquire();

    }

    public void turnOnScreen() {

            mWakeLock = mPowerManager.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK | PowerManager.ACQUIRE_CAUSES_WAKEUP, "tag");
            mWakeLock.acquire();
    }

}

When the app is sleeping or goes to other activity, the sensor still work. Any idea?

Answer 1

In your initial code you have not handled releasing the wake lock properly. When your activity is in onStop , unregister your listener and also release the wake lock held.

Answer 2

I took other way to fix this problem, because no one knows how to fixed this, So with this code I don't need to use SensorManager. Now I use two functions for starting and stoping sensor, I think is the only one solution.

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 this is my activity_main.xml

    <?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>

Thanks...

Also you can check this example in GitHub

Answer 3

Use the function wakeLock.setReferenceCounted(false). I have used it, and it works.