Unreleased Resource: Android Camera

An Android activity fails to release the Camera instance in its onPause(), onStop(), or onDestroy() event handlers.

The Android activity allocates a Camera instance that is not released in onPause(), onStop(), or onDestroy() callback. The Android OS invokes these callbacks whenever it needs to send the current activity to the background, or when it needs to temporarily destroy the activity when system resources are low. By failing to release the Camera object properly, the activity prevents other applications (or even future instances of the same application) from accessing the camera. Furthermore, maintaining possession of the Camera instance while the activity is paused can negatively impact the user's experience by unnecessarily draining the battery.

Example 1: The following code describes an Android activity that does not override the base onPause() method, which should be used to release the Camera object, nor does it properly release it during its shutdown sequence.

public class UnreleasedCameraActivity extends Activity {
  private Camera cam;

  @Override
  public void onCreate(Bundle state) {
      ...
  }

  @Override
  public void onRestart() {
      ...
  }

  @Override
  public void onStop() {
      cam.stopPreview();
  }
}