Android 唤醒锁问题答案

【问题标题】：Android wakeLock issueAndroid 唤醒锁问题
【发布时间】：2020-08-02 13:28:42
【问题描述】：

我有前台服务。

清单包含此权限：

<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS" />

在 Splash 活动中，我请求此权限一次：

Intent intent = new Intent();
        String packageName = context.getPackageName();
        PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
        if (!pm.isIgnoringBatteryOptimizations(packageName)) {
            intent.setAction(Settings.ACTION_REQUEST_IGNORE_BATTERY_OPTIMIZATIONS);
            intent.setData(Uri.parse("package:" + packageName));
        }
        context.startActivity(intent);

在 onCreate 服务方法中我调用 createAlarm 方法：

private void createAlarm() {
    wakeupIntent = PendingIntent.getBroadcast(getBaseContext(), 0, new Intent("com.android.internal.location.ALARM_WAKEUP"), 0);
    powerManager = (PowerManager) getSystemService(POWER_SERVICE);
    wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, getPackageName() + ":TrackService");
    wakeLock.acquire();

    dozeHandler = new Handler();
    Runnable heartbeat = new Runnable() {
        @Override
        public void run() {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
                try {
                    if (powerManager != null && powerManager.isDeviceIdleMode()) {
                        try {
                            Log.d("MainService", "In IDLE MODE");
                            wakeupIntent.send();
                        } catch (SecurityException | PendingIntent.CanceledException e) {
                            Log.d("MainService", "Heartbeat location manager keep-alive failed", e);
                        }
                    } else if (!powerManager.isDeviceIdleMode()) {
                        Log.d("MainService", "Device alive");
                    }
                } finally {
                    if (dozeHandler != null)
                        dozeHandler.postDelayed(this, 5000);
                }
        }
    };
    heartbeat.run();

    AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
    Intent intent = new Intent(this, MyWakefulReceiver.class);
    PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, intent, 0);
    if (Build.VERSION.SDK_INT >= 23) {
        alarmManager.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, 30000, pendingIntent);
    } else {
        alarmManager.setExact(AlarmManager.RTC_WAKEUP, 30000, pendingIntent);
    }
}

在所有初始化调用 setWakeLock 之后：

@SuppressLint("WakelockTimeout")
public void setWakeMode(Context context, int mode) {
    boolean wasHeld = false;
    if (wakeLock != null) {
        if (wakeLock.isHeld()) {
            wasHeld = true;
            wakeLock.release();
        }
        wakeLock = null;
    }
    PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
    wakeLock = pm.newWakeLock(mode | PowerManager.ON_AFTER_RELEASE, MainService.class.getName());
    wakeLock.setReferenceCounted(false);
    if (wasHeld) {
        wakeLock.acquire();
    }
}

我对这些功能感到困惑，因此我没有醒来，请帮助我。

【问题讨论】：

标签： android-service alarmmanager android-wake-lock android-doze android-powermanager

【解决方案1】：

boolean wasHeld = false;
if (wakeLock != null) {
    if (wakeLock.isHeld()) {
        wasHeld = true;
        wakeLock.release();
    }
    wakeLock = null;
}

只有在“wakeLock.isHeld()”时才将“wasHeld”设置为 true。只有在 'wasHeld' 为真时才调用获取：

if (wasHeld) {
    wakeLock.acquire();
}

取出 'if (wasHeld)...' 并调用 acquire 无论如何，我猜 wasHeld 总是假的，所以永远不会调用 acquire。

如果它仍然不起作用，根据 AndroidStudio 文档，您可以：

PowerManager powerManager = (PowerManager) getSystemService(POWER_SERVICE);
WakeLock wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
        "MyApp::MyWakelockTag");
wakeLock.acquire();

并调用

wakeLock.release();

完成后。

【讨论】：