android|android AlarmService

android AlarmService
分类: Android 2012-08-23 10:23 39人阅读 评论(0) 收藏 举报 实验2:使用AlarmService:
2.1通过AlarmService每个5秒发送一个广播,setRepeating时的类型为AlarmManager.ELAPSED_REALTIME。

AlarmManager am = (AlarmManager)getSystemService(ALARM_SERVICE);
am.setRepeating(AlarmManager.ELAPSED_REALTIME, firstTime, 5*1000, sender);

拔掉USB线,按下电源键,过一段时间再次打开屏幕,发现定时器没有继续计数。
2.2setRepeating是的类型设置为AlarmManager.ELAPSED_REALTIME_WAKEUP

AlarmManager am = (AlarmManager)getSystemService(ALARM_SERVICE);
am.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, firstTime, 5*1000, sender);

拔掉USB线,按下电源键,过一点时间再次打开屏幕,发现定时器一直在计数。

如此看来,使用WAKEUP才能保证自己想要的定时器一直工作,但是肯定会引起耗电量的增加


AlarmManager的使用机制有的称呼为全局定时器,有的称呼为闹钟。通过对它的使用,个人觉得叫全局定时器比较合适,其实它的作用和Timer有点相似。都有两种相似的用法:(1)在指定时长后执行某项操作(2)周期性的执行某项操作
AlarmManager对象配合Intent使用,可以定时的开启一个Activity,发送一个BroadCast,或者开启一个Service.
下面的代码详细的介绍了两种定时方式的使用:
(1)在指定时长后执行某项操作

Java代码android|android AlarmService
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android|android AlarmService
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  1. //操作:发送一个广播,广播接收后Toast提示定时操作完成
  2. Intent intent =new Intent(Main.this, alarmreceiver.class);
  3. intent.setAction("short");
  4. PendingIntent sender=
  5. PendingIntent.getBroadcast(Main.this, 0, intent, 0);
  6. //设定一个五秒后的时间
  7. Calendar calendar=Calendar.getInstance();
  8. calendar.setTimeInMillis(System.currentTimeMillis());
  9. calendar.add(Calendar.SECOND, 5);
  10. AlarmManager alarm=(AlarmManager)getSystemService(ALARM_SERVICE);
  11. alarm.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), sender);
  12. //或者以下面方式简化
  13. //alarm.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis()+5*1000, sender);
  14. Toast.makeText(Main.this, "五秒后alarm开启", Toast.LENGTH_LONG).show();
[java]view plain copy
  1. //操作:发送一个广播,广播接收后Toast提示定时操作完成
  2. Intent intent =new Intent(Main.this, alarmreceiver.class);
  3. intent.setAction("short");
  4. PendingIntent sender=
  5. PendingIntent.getBroadcast(Main.this, 0, intent, 0);
  6. //设定一个五秒后的时间
  7. Calendar calendar=Calendar.getInstance();
  8. calendar.setTimeInMillis(System.currentTimeMillis());
  9. calendar.add(Calendar.SECOND, 5);
  10. AlarmManager alarm=(AlarmManager)getSystemService(ALARM_SERVICE);
  11. alarm.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), sender);
  12. //或者以下面方式简化
  13. //alarm.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis()+5*1000, sender);
  14. Toast.makeText(Main.this, "五秒后alarm开启", Toast.LENGTH_LONG).show();
//注意:receiver记得在manifest.xml注册

Java代码android|android AlarmService
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android|android AlarmService
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  1. public static class alarmreceiver extends BroadcastReceiver{
  2. @Override
  3. public void onReceive(Context context, Intent intent) {
  4. // TODO Auto-generated method stub
  5. if(intent.getAction().equals("short")){
  6. Toast.makeText(context, "short alarm", Toast.LENGTH_LONG).show();
  7. }else{
  8. Toast.makeText(context, "repeating alarm",
  9. Toast.LENGTH_LONG).show();
  10. }
  11. }
  12. }
[java]view plain copy
  1. public static class alarmreceiver extends BroadcastReceiver{
  2. @Override
  3. public void onReceive(Context context, Intent intent) {
  4. // TODO Auto-generated method stub
  5. if(intent.getAction().equals("short")){
  6. Toast.makeText(context, "short alarm", Toast.LENGTH_LONG).show();
  7. }else{
  8. Toast.makeText(context, "repeating alarm",
  9. Toast.LENGTH_LONG).show();
  10. }
  11. }
  12. }
(2)周期性的执行某项操作

Java代码android|android AlarmService
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android|android AlarmService
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  1. Intent intent =new Intent(Main.this, alarmreceiver.class);
  2. intent.setAction("repeating");
  3. PendingIntent sender=PendingIntent
  4. .getBroadcast(Main.this, 0, intent, 0);
  5. //开始时间
  6. long firstime=SystemClock.elapsedRealtime();
  7. AlarmManager am=(AlarmManager)getSystemService(ALARM_SERVICE);
  8. //5秒一个周期,不停的发送广播
  9. am.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP
  10. , firstime, 5*1000, sender);
[java]view plain copy
  1. Intent intent =new Intent(Main.this, alarmreceiver.class);
  2. intent.setAction("repeating");
  3. PendingIntent sender=PendingIntent
  4. .getBroadcast(Main.this, 0, intent, 0);
  5. //开始时间
  6. long firstime=SystemClock.elapsedRealtime();
  7. AlarmManager am=(AlarmManager)getSystemService(ALARM_SERVICE);
  8. //5秒一个周期,不停的发送广播
  9. am.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP
  10. , firstime, 5*1000, sender);
AlarmManager的setRepeating()相当于Timer的Schedule(task,delay,peroid); 有点差异的地方时Timer这个方法是指定延迟多长时间
以后开始周期性的执行task;
AlarmManager的取消:(其中需要注意的是取消的Intent必须与启动Intent保持绝对一致才能支持取消AlarmManager)

【android|android AlarmService】
Java代码android|android AlarmService
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android|android AlarmService
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  1. Intent intent =new Intent(Main.this, alarmreceiver.class);
  2. intent.setAction("repeating");
  3. PendingIntent sender=PendingIntent
  4. .getBroadcast(Main.this, 0, intent, 0);
  5. AlarmManager alarm=(AlarmManager)getSystemService(ALARM_SERVICE);
  6. alarm.cancel(sender);
[java]view plain copy
  1. Intent intent =new Intent(Main.this, alarmreceiver.class);
  2. intent.setAction("repeating");
  3. PendingIntent sender=PendingIntent
  4. .getBroadcast(Main.this, 0, intent, 0);
  5. AlarmManager alarm=(AlarmManager)getSystemService(ALARM_SERVICE);
  6. alarm.cancel(sender);

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