当我的应用程序启动时,我想让它检查一个特定的警报(通过AlarmManager注册)是否已经设置并运行。谷歌的结果似乎表明没有办法做到这一点。这仍然正确吗?我需要做这个检查,以便在采取任何行动创建一个新的警报之前建议用户。
当前回答
请注意Alarm Manager的set方法的文档引用:
如果已经为此意图计划了一个警报(使用 由Intent.filterEquals定义的两个意图的相等性),然后它 将被移除,并被这个替换。
如果你知道你想要闹钟设置,那么你不需要费心检查它是否已经存在。每次你的应用启动时创建它。您将用相同的意图替换任何过去的警报。
如果您试图计算以前创建的警报还剩多少时间,或者您确实需要知道这样的警报是否存在,则需要使用不同的方法。要回答这些问题,请考虑在创建警报时保存共享pref数据。您可以存储闹钟设置时刻的时钟时间戳,您希望闹钟响起的时间,以及重复周期(如果您设置了重复闹钟)。
其他回答
Intent intent = new Intent("com.my.package.MY_UNIQUE_ACTION");
PendingIntent pendingIntent = PendingIntent.getBroadcast(
sqlitewraper.context, 0, intent,
PendingIntent.FLAG_NO_CREATE);
FLAG_NO_CREATE不是创建挂起意图,因此它给出布尔值false。
boolean alarmUp = (PendingIntent.getBroadcast(sqlitewraper.context, 0,
new Intent("com.my.package.MY_UNIQUE_ACTION"),
PendingIntent.FLAG_NO_CREATE) != null);
if (alarmUp) {
System.out.print("k");
}
AlarmManager alarmManager = (AlarmManager) sqlitewraper.context
.getSystemService(Context.ALARM_SERVICE);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,
System.currentTimeMillis(), 1000 * 60, pendingIntent);
在AlarmManager检查Pending Intent的值后,它给出true,因为AlarmManager更新了Pending Intent的标志。
boolean alarmUp1 = (PendingIntent.getBroadcast(sqlitewraper.context, 0,
new Intent("com.my.package.MY_UNIQUE_ACTION"),
PendingIntent.FLAG_UPDATE_CURRENT) != null);
if (alarmUp1) {
System.out.print("k");
}
根据我的经验,在最新版本的Android中,我认为它只允许广播消息唤醒警报,而不是直接启动服务。看看这个链接:https://developer.android.com/training/scheduling/alarms,上面写着:
报警器具有以下特点:
它们允许你在设定的时间和/或间隔内发射intent。 您可以将它们与广播接收器结合使用以启动服务和执行其他操作。
第二句话的关键词是“连词”。它明确指出,警报是为Broadcast设计的(这意味着不是为直接启动服务而设计的)。我尝试了几个小时使用一个PendingIntent与getService(),但不能让它工作,即使我确认挂起的意图是正确地使用:
pendingIntent.send(0);
对于“targetSdkVersion 29”,这没有工作..[不会触发onStartCommand()]:
Intent launchIntent = new Intent(context, MyService.class);
launchIntent.putExtra(Type.KEY, SERVER_QUERY);
PendingIntent pendingIntent =
PendingIntent.getService(context, 0, launchIntent, 0);
我可以验证警报正在运行使用:
adb shell dumpsys alarm | grep com.myapp
然而,这确实奏效了:
public static class AlarmReceiverWakeup extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
Log.i(TAG, "onReceive Alarm wakeup");
startService(context);
}
}
public static void scheduleAlarmWakeup(Context context) {
Intent broadcastIntent = new Intent(context, AlarmReceiverWakeup.class);
broadcastIntent.putExtra(Type.KEY, SERVER_QUERY);
PendingIntent pendingIntent =
PendingIntent.getBroadcast(context, 0, broadcastIntent, 0);
AlarmManager alarmManager =
(AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
// NOTE: using System.currentTimeMillis() fails w/ELAPSED_REALTIME_WAKEUP
// use SystemClock.elapsedRealtime() instead
alarmManager.setRepeating(
AlarmManager.ELAPSED_REALTIME_WAKEUP,
SystemClock.elapsedRealtime()+5000,
AlarmManager.INTERVAL_FIFTEEN_MINUTES/4,
getAlarmPendingIntent(context)
);
}
顺便说一下,这是Broadcast Receiver的AndroidManifest.xml条目:
<receiver android:name=".ServerQueryService$AlarmReceiverWakeup"
android:enabled="true">
<intent-filter>
<category android:name="android.intent.category.DEFAULT"/>
</intent-filter>
</receiver>
如果你的目标是Android 12(即目标SDK 31),那么,对于AlarmManager, PendingIntent不能在没有Mutable或Immutable标志的情况下创建。如果没有这个可变性标志,应用程序将抛出一个运行时错误。有关这方面的更多详细信息,请参阅本文档。下面的代码片段对我来说是有用的,它将帮助那些将应用程序定位于Android 12的人。
创建告警:
public static void setupReminderServiceAlarm ( Context context ) {
Log.d ( TAG, "Trying to setup reminder service alarm" );
if (!isReminderServiceAlarmSet ( context )) {
AlarmManager alarmManager = (AlarmManager) context.getApplicationContext ().getSystemService ( Context.ALARM_SERVICE );
Intent intent = new Intent ( context.getApplicationContext (), ReminderIntentReceiver.class );
intent.setAction ( REMINDER_INTENT_ACTION );
PendingIntent pendingIntent;
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.S) {
pendingIntent = PendingIntent.getBroadcast ( context.getApplicationContext (), REMINDER_INTENT_REQUEST_CODE, intent, PendingIntent.FLAG_IMMUTABLE );
} else {
pendingIntent = PendingIntent.getBroadcast ( context.getApplicationContext (), REMINDER_INTENT_REQUEST_CODE, intent, 0 );
}
alarmManager.setRepeating ( AlarmManager.RTC_WAKEUP, getReminderTriggerTime (), REMINDER_INTERVAL, pendingIntent );
Log.d ( TAG, "Reminder service alarm setup completed" );
}
}
查询告警是否已设置:
private static boolean isReminderServiceAlarmSet ( Context context ) {
Intent intent = new Intent ( context.getApplicationContext (), ReminderIntentReceiver.class );
intent.setAction ( REMINDER_INTENT_ACTION );
boolean isBackupServiceAlarmSet;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
PendingIntent.getBroadcast ( context.getApplicationContext (), REMINDER_INTENT_REQUEST_CODE, intent, PendingIntent.FLAG_IMMUTABLE | PendingIntent.FLAG_NO_CREATE );
isBackupServiceAlarmSet = (PendingIntent.getBroadcast ( context.getApplicationContext (), REMINDER_INTENT_REQUEST_CODE, intent, PendingIntent.FLAG_IMMUTABLE | PendingIntent.FLAG_NO_CREATE ) != null);
} else {
PendingIntent.getBroadcast ( context.getApplicationContext (), REMINDER_INTENT_REQUEST_CODE, intent, PendingIntent.FLAG_NO_CREATE );
isBackupServiceAlarmSet = (PendingIntent.getBroadcast ( context.getApplicationContext (), REMINDER_INTENT_REQUEST_CODE, intent, PendingIntent.FLAG_NO_CREATE ) != null);
}
Log.d ( TAG, "Reminder service alarm is " + (isBackupServiceAlarmSet ? "" : "not ") + "set already" );
return isBackupServiceAlarmSet;
}
取消之前设置的闹钟:
public static void cancelReminderServiceAlarm ( Context context ) {
Log.d ( TAG, "Reminder service alarm canceled" );
AlarmManager alarmManager = (AlarmManager) context.getApplicationContext ().getSystemService ( Context.ALARM_SERVICE );
Intent intent = new Intent ( context.getApplicationContext (), ReminderIntentReceiver.class );
intent.setAction ( REMINDER_INTENT_ACTION );
PendingIntent pendingIntent;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
pendingIntent = PendingIntent.getBroadcast ( context.getApplicationContext (), REMINDER_INTENT_REQUEST_CODE, intent, PendingIntent.FLAG_IMMUTABLE );
} else {
pendingIntent = PendingIntent.getBroadcast ( context.getApplicationContext (), REMINDER_INTENT_REQUEST_CODE, intent, 0 );
}
alarmManager.cancel ( pendingIntent );
pendingIntent.cancel ();
}
希望这个答案能帮助那些瞄准Android 12 / SDK 31+应用程序的人。此外,请确保在清单中添加此权限,以调度针对上述告警的告警。
<uses-permission android:name="android.permission.SCHEDULE_EXACT_ALARM"/>
刚找到另一个解决办法,似乎对我有用
Intent myIntent = new Intent(MainActivity.this, MyReceiver.class);
boolean isWorking = (PendingIntent.getBroadcast(MainActivity.this, 0, myIntent, PendingIntent.FLAG_NO_CREATE) != null);
if (isWorking) {Log.d("alarm", "is working");} else {Log.d("alarm", "is not working");}
if(!isWorking) {
pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0, myIntent, PendingIntent.FLAG_UPDATE_CURRENT);
alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
int timeNotif = 5 * 60 * 1000;//time in ms, 7*24*60*60*1000 for 1 week
Log.d("Notif", "Notification every (ms): " + timeNotif);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), timeNotif, pendingIntent);
}
我有两个闹钟。我使用带有额外内容的意图而不是行动来识别事件:
Intent i = new Intent(context, AppReciever.class);
i.putExtra("timer", "timer1");
问题是,不同的额外的意图(和警报)不会是唯一的。因此,为了能够识别哪个警报是活跃的或不活跃的,我必须定义diff requestCode-s:
boolean alarmUp = (PendingIntent.getBroadcast(context, MyApp.TIMER_1, i,
PendingIntent.FLAG_NO_CREATE) != null);
下面是如何创建警报的:
public static final int TIMER_1 = 1;
public static final int TIMER_2 = 2;
PendingIntent pending = PendingIntent.getBroadcast(context, TIMER_1, i,
PendingIntent.FLAG_CANCEL_CURRENT);
setInexactRepeating(AlarmManager.RTC_WAKEUP,
cal.getTimeInMillis(), AlarmManager.INTERVAL_DAY, pending);
pending = PendingIntent.getBroadcast(context, TIMER_2, i,
PendingIntent.FLAG_CANCEL_CURRENT);
setInexactRepeating(AlarmManager.RTC_WAKEUP,
cal.getTimeInMillis(), AlarmManager.INTERVAL_DAY, pending);
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