Question

我有一个叫振动器的服务。

[Service]
public class MyService : Service
{
    System.Threading.Timer timer;

    public MyService()
    {
    }

    public override StartCommandResult OnStartCommand(Intent intent, StartCommandFlags flags, int startId)
    {

        timer = new System.Threading.Timer( getCurrentPendingObjects, null, 100, Timeout.Infinite );

        return StartCommandResult.Sticky;
    }

    public override bool OnUnbind( Intent intent )
    {
        return base.OnUnbind( intent );
    }

    public override IBinder OnBind(Intent intent)
    {           
        binder = new MyServiceBinder( this );

        return binder;
    }   

    private void getCurrentPendingObjects( Object state )
    {
        Vibrator vibrator = (Vibrator)context.GetSystemService( Context.VibratorService );

        long [] vibrationPatern = new long[ ] { 100, 170 };
         vibrator.Vibrate( vibrationPatern, 1 );
    }
}

一切正常，直到我按下电源按钮导致屏幕关闭，设备进入睡眠模式。服务似乎继续工作，但振动器停止振动。

即使设备进入睡眠模式，如何保持振动器振动？

Answer 1

Wake locks将使系统保持活动状态，例如：

PowerManager powerManager = (PowerManager)Application.Context.GetSystemService(Application.PowerService);
Android.OS.PowerManager.WakeLock wakeLock = powerManager.NewWakeLock(WakeLockFlags.Partial, "StackOverFlow");
wakeLock.Acquire();

注意：完成后，释放锁定，因为这会缩短电池寿命：

wakeLock.Release();

注意：清单需要权限

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

Android文档：https://developer.android.com/reference/android/os/PowerManager.html

Answer 2

嗯，你似乎是一个有趣的应用程序......：P

我认为要保持服务正常运行，您需要WakeLock https://developer.xamarin.com/api/type/Android.OS.PowerManager+WakeLock/

唤醒锁定是一种机制，用于指示您的应用程序需要让设备保持运行状态。

任何使用WakeLock的应用程序都必须在应用程序清单的元素中请求android.permission.WAKE_LOCK权限。通过调用PowerManager.NewWakeLock（WakeLockFlags，String）获取唤醒锁。

调用PowerManager + WakeLock.Acquire获取唤醒锁定并强制设备保持在创建唤醒锁定时请求的级别。

完成后调用PowerManager + WakeLock.Release，不再需要锁定。尽快这样做是非常重要的，以避免过度耗尽设备的电池。

您可以这样做：

[Service]
public class MyService : Service
{
    System.Threading.Timer timer;

    private PowerManager _powerManager;
    private PowerManager.WakeLock _wakeLock;

    public MyService()
    {
    }

    public override StartCommandResult OnStartCommand(Intent intent, StartCommandFlags flags, int startId)
    {
         _powerManager = (PowerManager) GetSystemService(PowerService);
        _wakeLock = _powerManager.NewWakeLock(WakeLockFlags. Partial, "Vibrator");
        _wakeLock.Acquire();

        timer = new System.Threading.Timer( getCurrentPendingObjects, null, 100, Timeout.Infinite );

        return StartCommandResult.Sticky;
    }

    public override bool OnUnbind( Intent intent )
    {
         if (_wakeLock.IsHeld)
            _wakeLock.Release();
        return base.OnUnbind( intent );
    }

    public override IBinder OnBind(Intent intent)
    {           
        binder = new MyServiceBinder( this );

        return binder;
    }   

    private void getCurrentPendingObjects( Object state )
    {
        Vibrator vibrator = (Vibrator)context.GetSystemService( Context.VibratorService );

        long [] vibrationPatern = new long[ ] { 100, 170 };
         vibrator.Vibrate( vibrationPatern, 1 );
    }
}

此外，您还需要在清单中使用此权限

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

当你这么做的时候释放它：

if (_wakeLock.IsHeld)
      _wakeLock.Release();

Answer 3

如果您使用BroadcastReceiver，则可以连接到屏幕关闭操作。我可以在我的设备上启动服务，如下所示。

public class MyReceiver : BroadcastReceiver
{
    public override void OnReceive(Context context, Intent intent)
    {
        if (intent.Action.Equals(Intent.ActionScreenOff))
        {
             Application.Context.StartService(new Intent(Application.Context, typeof(MyService)));
        }
    }
}

只需注册接收器：

IntentFilter filter = new IntentFilter(Intent.ActionScreenOff);
RegisterReceiver(new MyReceiver(), filter);

按下电源按钮后振动器是否振动？

3 个答案: