xamarin/xamarin.forms 在锁屏电源唤醒时保持后台运行

[BroadcastReceiver(Enabled = true)]
public class AlarmService : BroadcastReceiver
{
//public event EventHandler WakeLockStatusChanged;
public override void OnReceive(Context context, Intent intent)
{
PowerManager pm = (PowerManager)context.GetSystemService(Context.PowerService);
PowerManager.WakeLock wl = pm.NewWakeLock(WakeLockFlags.Partial, "MyWakelockTag");
wl.Acquire();
//if (wl.IsHeld)
//{
// wl.Release();
//}
}
}

private void InitBroadcastReceiver()
{
_alarmService = new AlarmService();
Application.Context.RegisterReceiver(_alarmService, new IntentFilter(ConnectivityManager.ConnectivityAction));
} protected override void OnStart()
{
base.OnStart();
InitBroadcastReceiver();
} protected override void OnStop()
{
base.OnStop(); if (_alarmService != null)
{
Application.Context.UnregisterReceiver(_alarmService);
_alarmService = null;
} }

//获取电源锁，保持该服务在屏幕熄灭时仍然获取CPU时，保持运行
private void AcquireWakeLock()
{
if (null == _wakeLock)
{
PowerManager pm = (PowerManager)GetSystemService(Context.PowerService);
_wakeLock = pm.NewWakeLock(WakeLockFlags.Partial | WakeLockFlags.OnAfterRelease, "MyWakelockTag");
if (_wakeLock != null)
{
_wakeLock.Acquire();
}
}
} //释放设备电源锁
private void ReleaseWakeLock()
{
if (null != _wakeLock || _wakeLock.IsHeld)
{
_wakeLock.Release();
_wakeLock = null;
}
}