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Code Analyzer for Java
There is a newer version: 8.6.0.37351
Why is this an issue?
Optimizing resource usage and preventing unnecessary battery drain are critical considerations in Android development. Failing to release sensor
resources when they are no longer needed can lead to prolonged device activity, negatively impacting battery life. Common Android sensors, such as
cameras, GPS, and microphones, provide a method to release resources after they are not in use anymore.
This rule identifies situations where a sensor is not released after being utilized, helping developers maintain efficient and battery-friendly
applications.

   Missing call to release() method:
    
       android.os.PowerManager.WakeLock 
       android.net.wifi.WifiManager$MulticastLock 
       android.hardware.Camera 
       android.media.MediaPlayer 
       android.media.MediaRecorder 
       android.media.SoundPool 
       android.media.audiofx.Visualizer 
       android.hardware.display.VirtualDisplay 
    
  
   Missing call to close() method
    
       android.hardware.camera2.CameraDevice 
    
  
   Missing call to removeUpdates() method:
    
       android.location.LocationManager 
    
  
   Missing call to unregisterListener() method:
    
       android.hardware.SensorManager 
    
  

How to fix it
Ensure that resources are released when they are no longer needed. This can be done by calling the appropriate release method, such as
release(), removeUpdates(), unregisterListener(), or stop().
Code examples

   android.os.PowerManager.WakeLock 

Noncompliant code example
public void method() {
  PowerManager powerManager = (PowerManager) getSystemService(POWER_SERVICE);
  PowerManager.WakeLock wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "My Wake Lock");
  wakeLock.acquire(); // Noncompliant
  // do some work...
}

Compliant solution
public void method() {
  PowerManager powerManager = (PowerManager) getSystemService(POWER_SERVICE);
  PowerManager.WakeLock wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "My Wake Lock");
  wakeLock.acquire(); // Compliant
  // do some work...
  wakeLock.release();
}


   android.media.MediaPlayer 

Noncompliant code example
public void method() {
  MediaPlayer mediaPlayer = MediaPlayer.create(context, R.raw.sound_file_1);
  mediaPlayer.start(); // Noncompliant
  // do some work...
}

Compliant solution
public void onCreate() {
  MediaPlayer mediaPlayer = MediaPlayer.create(context, R.raw.sound_file_1);
  mediaPlayer.start(); // Compliant
  // do some work...
  wakeLock.release();
}


   android.hardware.SensorManager 

Noncompliant code example
public void method() {
  SensorManager sensorManager = getSystemService(SENSOR_SERVICE);
  Sensor accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
  sensorManager.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL); // Noncompliant
  // do some work...
}

Compliant solution
public void method() {
  SensorManager sensorManager = getSystemService(SENSOR_SERVICE);
  Sensor accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
  sensorManager.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL); // Compliant
  // do some work...
  sensorManager.unregisterListener(this);
}

Resources
Documentation

   Android - LocationManager 
   Android - PowerManager.WakeLock 
   Android - WifiManager.MulticastLock 
   Android - MediaProjection 
   Android - MediaPlayer 
   Android - MediaRecorder 
   Android - SoundPool 
   Android - Visualizer 
   Android - SensorManager 
   Android - Keep the device awake 
   Android - MediaPlayer Overview 
   Android - Sensors Overview