AlarmManager的使用
AlarmManager的作用文檔中的解釋是:在特定的時刻爲我們廣播一個指定的Intent。簡單的說就是我們設定一個時間,然後在該時間到來時,AlarmManager爲我們廣播一個我們設定的Intent。
對應AlarmManager更深層的瞭解可以參考:
http://www.programbbs.com/doc/5888.htm
http://jinguo.iteye.com/blog/799778
android提供了四種類型的鬧鐘:
❑ ELAPSED_REALTIME
在指定的延時過後,發送廣播,但不喚醒設備。
❑ ELAPSED_REALTIME_WAKEUP
在指定的演示後,發送廣播,並喚醒設備
延時是要把系統啓動的時間SystemClock.elapsedRealtime()算進去的,具體用法看代碼。
❑ RTC
在指定的時刻,發送廣播,但不喚醒設備
❑ RTC_WAKEUP
在指定的時刻,發送廣播,並喚醒設備
AlarmManager提供的方法:
❑ void set(int type, long triggerAtTime, PendingIntent operation)
設置一個鬧鐘
❑ void setRepeating(int type, long triggerAtTime, long interval, PendingIntent operation)
設置一個會重複的鬧鐘
❑ void setInexactRepeating(int type, long triggerAtTime, long interval, PendingIntent operation)
設置一個重複鬧鐘的不精確版本,它相對而言更節能(power-efficient)一些,因爲系統可能會將幾個差不多的鬧鐘合併爲一個來執行,減少設備的喚醒次數。
內置的幾個interval爲:
INTERVAL_FIFTEEN_MINUTES
INTERVAL_HALF_HOUR
INTERVAL_HOUR
INTERVAL_HALF_DAY
INTERVAL_DAY
如果你將其設爲DAY,那麼可能這一天中的所有鬧鐘都會被合併掉。
❑ void cancel(PendingIntent operation)
取消一個設置的鬧鐘
❑ void setTimeZone(String timeZone)
設置系統的默認時區。需要android.permission.SET_TIME_ZONE權限
- // 首先創建Receiver
- public class AlarmReceiver extends BroadcastReceiver {
- @Override
- public void onReceive(Context context, Intent intent) {
- Toast.makeText(context, "alarm", Toast.LENGTH_SHORT).show();
- }
- }
// 首先創建Receiver
public class AlarmReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
Toast.makeText(context, "alarm", Toast.LENGTH_SHORT).show();
}
}
- // manifest中申明,並不需要intent-filter,我們是明確指定發到哪個receiver的
- <receiver android:name="yuan.receivers.AlarmReceiver" />
// manifest中申明,並不需要intent-filter,我們是明確指定發到哪個receiver的 <receiver android:name="yuan.receivers.AlarmReceiver" />
PendingIntent:簡單的說就是在Intent上在加個指定的動作。Intent的話,我們還需要在執行startActivity、startService或sendBroadcast才能使Intent有用。而PendingIntent的話就是將這個動作包含在內了,如PendingIntent.getBroadcast就包含了sendBroadcast的動作。
5s後發送指定廣播
- AlarmManager alarmMgr = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
- Intent intent = new Intent(getApplicationContext(), AlarmReceiver.class);
- int requestCode = 0;
- PendingIntent pendIntent = PendingIntent.getBroadcast(getApplicationContext(),
- requestCode, intent, PendingIntent.FLAG_UPDATE_CURRENT);
- // 5秒後發送廣播,只發送一次
- int triggerAtTime = SystemClock.elapsedRealtime() + 5 * 1000;
- alarmMgr.set(AlarmManager.ELAPSED_REALTIME, triggerAtTime, pendIntent);
AlarmManager alarmMgr = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(getApplicationContext(), AlarmReceiver.class);
int requestCode = 0;
PendingIntent pendIntent = PendingIntent.getBroadcast(getApplicationContext(),
requestCode, intent, PendingIntent.FLAG_UPDATE_CURRENT);
// 5秒後發送廣播,只發送一次
int triggerAtTime = SystemClock.elapsedRealtime() + 5 * 1000;
alarmMgr.set(AlarmManager.ELAPSED_REALTIME, triggerAtTime, pendIntent);
5s後發送指定廣播,然後每個10秒重複發送廣播
- AlarmManager alarmMgr = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
- Intent intent = new Intent(getApplicationContext(), AlarmReceiver.class);
- int requestCode = 0;
- PendingIntent pendIntent = PendingIntent.getBroadcast(getApplicationContext(),
- requestCode, intent, PendingIntent.FLAG_UPDATE_CURRENT);
- // 5秒後發送廣播,然後每個10秒重複發廣播。廣播都是直接發到AlarmReceiver的
- int triggerAtTime = SystemClock.elapsedRealtime() + 5 * 1000;
- int interval = 10 * 1000;
- alarmMgr.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, triggerAtTime, interval, pendIntent);
AlarmManager alarmMgr = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(getApplicationContext(), AlarmReceiver.class);
int requestCode = 0;
PendingIntent pendIntent = PendingIntent.getBroadcast(getApplicationContext(),
requestCode, intent, PendingIntent.FLAG_UPDATE_CURRENT);
// 5秒後發送廣播,然後每個10秒重複發廣播。廣播都是直接發到AlarmReceiver的
int triggerAtTime = SystemClock.elapsedRealtime() + 5 * 1000;
int interval = 10 * 1000;
alarmMgr.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, triggerAtTime, interval, pendIntent);
取消一個鬧鐘
- AlarmManager alarmMgr = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
- Intent intent = new Intent(getApplicationContext(), AlarmReceiver.class);
- PendingIntent pendIntent = PendingIntent.getBroadcast(getApplicationContext(),
- 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
- // 與上面的intent匹配(filterEquals(intent))的鬧鐘會被取消
- alarmMgr.cancel(pendIntent);