我设置了一个警报，接收器启动了一个前台服务，该服务每隔几秒钟将数据发送到Firebase。当屏幕打开时，该服务被终止（我已经注册了屏幕接收器）。服务终止后，我会在20秒内设置另一个警报。我在服务启动或终止时发送时间戳（在onCreate（）和onDestroy（）方法中）。当我检查Firebase时，有6个小时的间隔根本没有发出警报。 这来自firebase数据：
2019-06-20 21:25:08开始
2019-06-20 21:25:08结束
2019-06-20 21:25:29开始
2019-06-20 21:25:29结束
2019-06-20 21:25:49开始
2019-06-20 21:35:26结束
2019-06-21 03:47:46开始
2019-06-21 08:48:02结束
2019-06-21 08:48:47开始
2019-06-21 08:55:55结束
2019-06-21 08:56:15开始
2019-06-21 08:56:15结束
AlarmReceiver.java：
if (PendingIntent.getBroadcast(context, 0, intentService, PendingIntent.FLAG_NO_CREATE) == null) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
context.startForegroundService(intentService);
} else {
context.startService(intentService);
}
}
MyService.java：
public void onCreate() {
super.onCreate();
Log.d("created","service");
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
PowerManager powerManager = (PowerManager) getSystemService(POWER_SERVICE);
wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
"MyApp::MyWakelockTag");
wakeLock.acquire();
mDatabase = FirebaseDatabase.getInstance().getReference();
username = sharedPreferences.getString("Username","invalid");
mDatabase.child(username).child("ServiceData").push().setValue("started");
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
if(intent != null)
{
if(mReceiver!=null){
unregisterReceiver(mReceiver);
}
PendingIntent pendingIntent =
PendingIntent.getActivity(this, 0, intent, 0);
Notification notification =
new NotificationCompat.Builder(this, getString(R.string.channelId))
.setContentTitle("CureFit")
.setContentText("Foreground process running")
.setSmallIcon(R.drawable.curefit)
.setContentIntent(pendingIntent)
.setColor(getResources().getColor(R.color.colorPrimaryDark))
.build();
startForeground(1, notification);
PowerManager powerManager = (PowerManager) getSystemService(POWER_SERVICE);
if(powerManager.isScreenOn())
stopSelf();
initializeSensorManager();
final IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
filter.addAction(Intent.ACTION_SCREEN_OFF);
mReceiver = new ScreenReceiver();
registerReceiver(mReceiver, filter);
Log.d("Started ", "foreground ");
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
username = sharedPreferences.getString("Username","invalid");
}
return super.onStartCommand(intent, flags, startId);
}
private void initializeSensorManager() {
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
Sensor mAccelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
sensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_FASTEST);
}
@Override
public void onSensorChanged(SensorEvent event) {
//Log.d("Sensor","changed");
if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
if (prevValues == null
|| Calendar.getInstance().getTimeInMillis()-prevTime >8000){
prevValues[0] = event.values[0];
prevValues[1] = event.values[1];
prevValues[2] = event.values[2];
Log.d("", "LOG SENSOR CHANGE");
Double sensorValue = MathUtil.magnitude(prevValues);
Calendar calendar = Calendar.getInstance();
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor editor = sharedPreferences.edit();
prevTime = calendar.getTimeInMillis();
editor.putLong("Last_sent", calendar.getTimeInMillis());
editor.putFloat("Last_data_sent", (float) MathUtil.magnitude(prevValues));
editor.apply();
Log.d("accelerometer value", String.valueOf(MathUtil.magnitude(prevValues)));
try {
//String id = mDatabase.child(username).push().getKey();
long timestamp = calendar.getTimeInMillis();
Record r = new Record(timestamp, sensorValue);
mDatabase.child(username).child("data").push().setValue(r);
// myOutWriter.append(String.valueOf(timestamp));
// myOutWriter.append("\n");
} catch (Exception e) {
e.printStackTrace();
NotificationCompat.Builder builder = new NotificationCompat.Builder(this, "1st channel")
.setSmallIcon(R.drawable.curefit)
.setContentTitle("Sleep tracker")
.setContentText(e.getMessage())
.setPriority(NotificationCompat.PRIORITY_DEFAULT);
NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this);
notificationManager.notify(2, builder.build());
}
}
}
}
@Override
public void onAccuracyChanged(Sensor arg0, int arg1){
}
@Override
public void onDestroy(){
Log.d("killed","Service");
if (sensorManager != null) {
sensorManager.unregisterListener(this);
sensorManager = null;
}
unregisterReceiver(mReceiver);
Calendar calendar = Calendar.getInstance();
mDatabase.child(username).child("ServiceData").push().setValue("ended");
AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
Intent i = new Intent(this, AlarmReceiver.class);
PendingIntent pi = PendingIntent.getBroadcast(this, 0, i, 0);
// am.setRepeating(AlarmManager.RTC_WAKEUP,
// SystemClock.elapsedRealtime() + 5 * 1000,
// 5 * 1000, pi);
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
//am.setExactAndAllowWhileIdle(AlarmManager.ELAPSED_REALTIME_WAKEUP,SystemClock.elapsedRealtime() + 20 * 1000 ,pi);
am.setAlarmClock(new AlarmManager.AlarmClockInfo(Calendar.getInstance().getTimeInMillis()+20000,pi),pi);
}
else {
am.set(AlarmManager.ELAPSED_REALTIME_WAKEUP,SystemClock.elapsedRealtime() + 20 * 1000 ,pi);
}
wakeLock.release();
}
这可能是电话不允许拨打警报。可能是什么原因？