Android 使用 wakelock.release() 关闭应用程序时应用程序崩溃

Question

我有一个简单的手电筒应用程序，运行良好，但当用户关闭该应用程序时，该应用程序崩溃了。我认为问题出在唤醒锁上。

闪光灯开启时唤醒锁开启，闪光灯关闭时唤醒锁关闭。这工作正常，但一旦用户按下返回或主页，应用程序就会崩溃。

我的日志数据：

10-24 09:52:45.235: E/AndroidRuntime(6614): Process: r1d.org.uk.flashlight, PID: 6614 10-24 09:52:45.235: E/AndroidRuntime(6614): java.lang.RuntimeException: Unable to destroy activity {r1d.org.uk.flashlight/r1d.org.uk.flashlight.MainActivity}: java.lang.RuntimeException: WakeLock under-locked MyWakelockTag 10-24 09:52:45.235: E/AndroidRuntime(6614): at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3812)

主要活动：

public class MainActivity extends Activity {

    private ImageView lightToggle;
    private ImageButton lightSwitch;
    Camera camera = null;
    Parameters parameters;
    Boolean isOn = false;
    int lightON = R.drawable.on;
    int lightOFF = R.drawable.off;
    int switchON = R.drawable.switch_on;
    int switchOFF = R.drawable.switch_off;
    Boolean hasFlash;
    PowerManager powerManager;
    PowerManager.WakeLock wakeLock;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        AdManager ads = new AdManager(this);
        lightToggle = (ImageView) findViewById(R.id.lightOn);
        lightSwitch = (ImageButton) findViewById(R.id.lightSwitch);
        Context context = this;
        hasFlash = context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);
        powerManager = (PowerManager) getSystemService(POWER_SERVICE);
        wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "MyWakelockTag");

        if(!hasFlash){
            ContextThemeWrapper themedContext;
            if ( Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ) {
                themedContext = new ContextThemeWrapper( MainActivity.this, android.R.style.Theme_Holo_Light_Dialog_NoActionBar );
            }
            else {
                themedContext = new ContextThemeWrapper( MainActivity.this, android.R.style.Theme_Light_NoTitleBar );
            }
            AlertDialog.Builder builder = new AlertDialog.Builder(themedContext);
            builder.setTitle(getResources().getString(R.string.notsupported))
                    .setMessage(getResources().getString(R.string.notsupportedinfo))
                    .setIcon(android.R.drawable.ic_dialog_alert)
                    .setNegativeButton(getResources().getString(R.string.ok), new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int i) {
                            dialog.cancel();
                        }
                    });
            builder.show();
        }
        turnOn();
        lightSwitch.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(isOn){
                    turnOff();
                } else {
                    turnOn();
                }
            }
        });
    }
    private void turnOn(){
        lightToggle.setImageDrawable(getResources().getDrawable(lightON));
        lightSwitch.setImageDrawable(getResources().getDrawable(switchON));
        wakeLock.acquire();
        if(hasFlash) {
            camera = Camera.open();
            parameters = camera.getParameters();
            parameters.setFlashMode(Parameters.FLASH_MODE_TORCH); //FLASH_MODE_ON
            camera.setParameters(parameters);
        }
        isOn = true;
    }
    private void turnOff(){
        lightToggle.setImageDrawable(getResources().getDrawable(lightOFF));
        lightSwitch.setImageDrawable(getResources().getDrawable(switchOFF));
        wakeLock.release();
        if(hasFlash) {
            parameters.setFlashMode(Parameters.FLASH_MODE_OFF);
            camera.setParameters(parameters);
            camera.release();
            camera = null;
        }
        isOn = false;
    }
    @Override
    public void onDestroy() {
        turnOff();
        super.onDestroy();
    }
    @Override
    public void onPause(){
        turnOff();
        super.onPause();
    }
    @Override
    public void onResume(){
        turnOn();
        super.onResume();
    }
}

Answer 1

在 onDestroy 中，您正在尝试释放您已在 onPause 中释放的唤醒锁。这应该有效：

if (wakeLock.isHeld()) {
    wakeLock.release();
}

Android 使用 wakelock.release() 关闭应用程序时应用程序崩溃

Android app crashed when closing app using wakelock.release()

java

android

power-management

android-wake-lock

wakelock