跳过我的回答
我看到过类似的问题，但没有合适或正确的答案，有的甚至是自相矛盾的。
问题很简单： alarmManager不能长时间（超过几个小时）工作吗？
我有一个应用程序，它有一个消息数组。在第一次运行时，每个msg都会得到一个个人计时（Calendar obj），应用程序为每个msg设置一个alarmManager，并将所有的消息保存在sharedPrefference。下面的代码（当然我只复制了相关的代码）工作正常，即使我重启设备（感谢sharedPref）几个小时，然后停止发送通知。
如果我把整个msg时间设置为短期（比如说：10个msg，每5分钟1个），它的工作效果很好，而且都能发送。但如果我把它安排为每小时，它只在前2-3小时工作。
我看到一些答案说 alarmManager 不适合长期使用，而其他答案则说它是完美的服务 :( 谁能给我一个专业的答案？
我也试过 alarmManager.setAlarmClock()和setExactAndAllowWhileIdle()，但结果一样。
好了，经过长时间的挖掘，我想我弄明白了。现在可以用了，重启后，通知又回来了。
我把我的代码贴在这里，首先是为了任何人寻找解决方案，其次--我想听听你的意见--如果我做的对不对等等。Tnx
msg.activity
private void addAlerts (MyMsg myMsg) {
MyReceiver rc = new MyReceiver ();
for (int i = 1; i < myMsg.totalMsgNum; i++)
rc.setSingleNotifications (this, myMsg.msg[i]);
}
MyReciever.java
public class MyReceiver extends BroadcastReceiver {
final String CHANNEL_ID = "777";
SharedPreferences pref;
SharedPreferences.Editor editor;
@Override
public void onReceive (Context context, Intent intent) {
// get the relevant content
pref = context.getSharedPreferences ("SAVED_FILE", Context.MODE_PRIVATE);
int atMsgNum = pref.getInt ("CURRENT", 1);
String json = pref.getString ("USER_OBJ", "");
Gson gson = new Gson ();
User user = gson.fromJson (json, User.class);
String titleStr = user.msg[atMsgNum].title;
String contentStr = user.msg[atMsgNum].msg;
// update current msg num
editor = pref.edit ();
editor.putInt ("CURRENT", atMsgNum + 1);
editor.commit ();
// intent for showing the msg activity
intent.setClass (context, OnPressNotificationActivity.class);
intent.putExtra ("ID", atMsgNum);
intent.setFlags (Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
// notification
createNotificationChannel (context);
TaskStackBuilder stackBuilder = TaskStackBuilder.create (context);
stackBuilder.addNextIntentWithParentStack (intent);
PendingIntent pendingIntent = stackBuilder.getPendingIntent (atMsgNum, 0);
NotificationCompat.Builder builder;
builder = new NotificationCompat.Builder (context, CHANNEL_ID)
.setSmallIcon (R.drawable.single_pics_logo)
.setContentTitle (titleStr)
.setContentText (contentStr)
.setStyle (new NotificationCompat.BigTextStyle ()
.bigText (contentStr))
.setPriority (NotificationCompat.PRIORITY_HIGH)
.setContentIntent (pendingIntent)
.setAutoCancel (true)
.setBadgeIconType (NotificationCompat.BADGE_ICON_SMALL)
.setVisibility (NotificationCompat.VISIBILITY_PUBLIC);
NotificationManagerCompat notificationManager = NotificationManagerCompat.from (context);
notificationManager.notify (atMsgNum, builder.build ());
}
public void setSingleNotifications (Context context, Msg msg) {
Intent intent = new Intent (context, MyReceiver.class);
PendingIntent alarmIntent = PendingIntent.getBroadcast (context, msg.num, intent, PendingIntent.FLAG_UPDATE_CURRENT);
Calendar calendar = Calendar.getInstance ();
calendar.setTimeInMillis (System.currentTimeMillis ());
calendar.set (Calendar.YEAR, msg.calendar.get (Calendar.YEAR));
calendar.set (Calendar.MONTH, msg.calendar.get (Calendar.MONTH));
calendar.set (Calendar.DAY_OF_MONTH, msg.calendar.get (Calendar.DAY_OF_MONTH));
calendar.set (Calendar.HOUR_OF_DAY, msg.calendar.get (Calendar.HOUR_OF_DAY));
calendar.set (Calendar.MINUTE, msg.calendar.get (Calendar.MINUTE));
calendar.set (Calendar.SECOND, msg.calendar.get (Calendar.SECOND));
calendar.add (Calendar.SECOND, 2);
AlarmManager alarmManager = (AlarmManager) context.getSystemService (ALARM_SERVICE);
AlarmManager.AlarmClockInfo almInfo = new AlarmManager.AlarmClockInfo (calendar.getTimeInMillis (), null);
alarmManager.setAlarmClock (almInfo, alarmIntent);
}
private void createNotificationChannel (Context context) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
{
CharSequence name = "myMsgApp";
String description = "daily alert";
int importance = NotificationManager.IMPORTANCE_HIGH;
NotificationChannel channel = new NotificationChannel (CHANNEL_ID, name, importance);
channel.setDescription (description);
NotificationManager notificationManager = context.getSystemService (NotificationManager.class);
notificationManager.createNotificationChannel (channel);
}
}
}
重启接收机.java / 用于重启
public class RestartReceiver extends BroadcastReceiver {
@Override
public void onReceive (Context context, Intent intent) { // restarts alarms only when device restart
if (intent.getAction ().equals ("android.intent.action.BOOT_COMPLETED")) {
SharedPreferences sharedPreferences = context.getSharedPreferences ("SAVED_FILE", context.MODE_PRIVATE);
String json = sharedPreferences.getString ("USER_OBJ", "");
Intent in = new Intent (context, RestartService.class);
in.setFlags (Intent.FLAG_ACTIVITY_NEW_TASK); // ??
in.putExtra ("JSON_STRING", json);
in.putExtra ("CURRENT", sharedPreferences.getInt ("CURRENT", 1));
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
context.startForegroundService (in);
else
context.startService (in);
}
}
}
重新启动服务.java
public class RestartService extends IntentService {
public RestartService () {
super ("RestartService");
}
public RestartService (String name) {
super (name);
}
@Override
protected void onHandleIntent (@Nullable Intent intent) {
String json = intent.getExtras ().getString ("JSON_STRING", "");
Gson gson = new Gson ();
User user = gson.fromJson (json, User.class);
user.atMsgNum = intent.getExtras ().getInt ("CURRENT", 1);
MyReceiver rc = new MyReceiver ();
for (int i = user.atMsgNum; i < user.totalMsgNum; i++)
rc.setSingleNotifications (this, user.msg [i]);
}
}
列表 包括：
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<receiver android:name=".MyReceiver">
<intent-filter>
<action android:name="android.intent.action.INPUT_METHOD_CHANGED" />
<action android:name="android.media.action.DISPLAY_NOTIFICATION" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
<receiver
android:name=".RestartReceiver"
android:enabled="true">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
<service android:name="myPackageName.RestartService"
android:exported="false"/>