Android 使用setExact()在每天的特定时间触发警报
我每天都试图在特定的时间触发一次警报。但像所有其他人一样,我使用的是Android 使用setExact()在每天的特定时间触发警报,android,alarmmanager,Android,Alarmmanager,我每天都试图在特定的时间触发一次警报。但像所有其他人一样,我使用的是setExact()而不是setRepeating()。警报在正确的时间触发。但一旦它开火,它每5秒就会重复一次。我怎样才能在一天中的特定时间触发它一次?这是我的密码: MainActivity.java: public class MainActivity extends AppCompatActivity implements Observer { private AlarmManager alarmManager
setExact()
而不是setRepeating()
。警报在正确的时间触发。但一旦它开火,它每5秒就会重复一次。我怎样才能在一天中的特定时间触发它一次?这是我的密码:
MainActivity.java:
public class MainActivity extends AppCompatActivity implements Observer {
private AlarmManager alarmManager = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
BroadcastObserver.getInstance().addObserver(this);
}
@Override
public void update(Observable o, Object arg) {
Log.e("MainActivity", "Alarm set through observer");
cancelAlarm();
setAlarm();
}
@Override
protected void onStart() {
super.onStart();
if (!checkAlarm()) {
setAlarm();
}
}
public void setAlarm() {
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, 14);
calendar.set(Calendar.MINUTE, 13);
calendar.set(Calendar.SECOND, 0);
alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(this, MyReceiver.class);
intent.setAction(MyReceiver.ACTION_RECEIVER);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 1001, intent, PendingIntent.FLAG_CANCEL_CURRENT);
alarmManager.setExact(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
}
private boolean checkAlarm() {
Intent intent = new Intent(this, MyReceiver.class);
intent.setAction(MyReceiver.ACTION_RECEIVER);
boolean isSet = PendingIntent.getBroadcast(this, 1001, intent, PendingIntent.FLAG_NO_CREATE) != null;
Log.e("MainActivity", isSet + " :Alarm is set");
return isSet;
}
@Override
protected void onStop() {
super.onStop();
cancelAlarm();
}
private void cancelAlarm() {
Intent intent = new Intent(this, MyReceiver.class);
intent.setAction(MyReceiver.ACTION_RECEIVER);
final PendingIntent pendingIntent =
PendingIntent.getBroadcast(MainActivity.this, 1001, intent,
PendingIntent.FLAG_NO_CREATE);
if (pendingIntent != null) {
alarmManager.cancel(pendingIntent);
pendingIntent.cancel();
}
}
}
广播接收机:
public class MyReceiver extends BroadcastReceiver {
public static final String ACTION_RECEIVER = "Receiver";
@Override
public void onReceive(Context context, Intent intent) {
Log.e("MainActivity", "triggered");
BroadcastObserver.getInstance().updateValue(intent);
}
}
广播观察员:
public class BroadcastObserver extends Observable {
private static BroadcastObserver instance = new BroadcastObserver();
public static BroadcastObserver getInstance(){
return instance;
}
private BroadcastObserver(){}
public void updateValue(Object data) {
synchronized (this) {
setChanged();
notifyObservers(data);
}
}
}
一旦它开火,它每5秒就会重复一次
您正在将给定日期的闹钟设置为14:13。当警报触发时,将通知观察者,并设置完全相同的警报(14:13)
此时我们已经过了14:13,因此警报将立即触发,再次通知观测者,导致上述步骤的无限循环
最简单的解决方案可能是在设置警报时检查时间,如果是过去,则在警报中添加一天:
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, 14);
calendar.set(Calendar.MINUTE, 13);
calendar.set(Calendar.SECOND, 0);
if (calendar.before(Calendar.getInstance())) {
calendar.add(Calendar.DAY_OF_YEAR, 1);
}
为避免内存泄漏,您需要在适当的时候移除观察者
:
@Override
protected void onDestroy() {
BroadcastObserver.getInstance().deleteObserver(this);
super.onDestroy();
}
此外,取消
update()
中的报警也是多余的。这不是重复报警,因此在报警触发后取消报警是没有意义的。为什么每天都取消并设置报警?您是否应该使用setRepeating每天重复?setRepeating()
更倾向于优化,它可能在达到特定目标后随时触发。因此,触发警报并不那么准确。这是我在书中看到的。请发布BroadcastObserver
的代码@地球人吉姆