由於我將始終有有限數量的通知,並且我可以提前計算已用時間,所以看起來AlarmManager
和BroadcastReceiver
的組合工作得很好。這裏是我是如何實現這一點:
我首先創建一個BroadcastReceiver
public class NotificationReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
//Get handle to system notification manager
NotificationManager mNM = (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);
//Get message from intent
Bundle bundle = intent.getExtras();
CharSequence text = bundle.getString("notification_message");
// Set the icon, scrolling text and timestamp
Notification notification = new Notification(R.drawable.notification_icon, text, System.currentTimeMillis());
// The PendingIntent to launch our activity if the user selects this notification
PendingIntent contentIntent = PendingIntent.getActivity(context, 0, new Intent(context, MainActivity.class), 0);
// Set the info for the views that show in the notification panel.
notification.setLatestEventInfo(context, context.getText(R.string.app_name),text, contentIntent);
// Set Flags
notification.flags |= Notification.FLAG_AUTO_CANCEL;
// Send the notification.
mNM.notify(R.string.notification, notification);
}
}
然後,我創建了一個使用AlarmManager
創建一個類/取消發送消息給BroadcastReceiver
public class NotificationSender {
private AlarmManager mAlarmManager;
private Context mContext;
private Intent mIntent;
public NotificationSender(Context context){
this.mAlarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
this.mIntent = new Intent(context, NotificationReceiver.class);
this.mContext = context;
}
public void setAlarm(Long etaMillis, int accumulator){
//Create intent to send to Receiver
this.mIntent.putExtra("notification_message","Message");
//Use accumulator as requestCode so we can cancel later
PendingIntent sender = PendingIntent.getBroadcast(this.mContext, accumulator, this.mIntent, PendingIntent.FLAG_UPDATE_CURRENT);
//Set Alarm
mAlarmManager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, etaMillis, sender);
}
public void cancelAlarms(){
//requestCode (accumulator) will always be a multiple of 10 and less than 100
for (int x = 10; x <= 100; x += 10){
PendingIntent operation = PendingIntent.getBroadcast(this.mContext, x, this.mIntent, PendingIntent.FLAG_UPDATE_CURRENT);
mAlarmManager.cancel(operation);
}
}
public void createAlarms(PreferenceHelper prefs){
//Calculate time notifications are due and set an alarm for each one
//PreferenceHelper is a class to help pull values from shared preferences
Date currentTime = new Date();
for (int i = prefs.getNotificationInterval(); i <= 100; i += prefs.getNotificationInterval()) {
if (i > prefs.getAccumulator()) {
this.setAlarm(SystemClock.elapsedRealtime() + calculateETA(i, prefs).getTime() - currentTime.getTime(), i);
}
}
}
public void refreshAlarms(PreferenceHelper prefs){
this.cancelAlarms();
if (prefs.isNotificationsEnabled()) this.createAlarms(prefs);
}
}
報警
重要的部分是使用累加器作爲requestCode
,因此我們可以稍後取消所有的報警。
最後我在onCreate()
調用refreshAlarms()
並且每當用戶修改是相關的調度通知偏好使用的NotificationSender
類在我的活動。重新啓動手機將清除所有鬧鐘,以便在通知開始前必須重新啓動應用程序。如果系統碰巧殺死了進程,報警仍然會在適當的時候觸發。
即使我殺了應用程序,它仍會運行嗎? –