android - 在 Android 中设置警报管理器

Question

我正在按照 Android 开发人员文档和其他一些教程来创建一个每天下午 4 点触发并唤醒 CPU 的警报管理器，以下是我的代码:

    private AlarmManager alarmMgr;
    private PendingIntent alarmIntent;
    BroadcastReceiver br;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    alarmMgr = (AlarmManager)getApplicationContext().getSystemService(Context.ALARM_SERVICE);
    // Set the alarm to start at approximately 2:00 p.m.
    Calendar calendar = Calendar.getInstance();
    calendar.setTimeInMillis(System.currentTimeMillis());
    calendar.set(Calendar.HOUR_OF_DAY, 16);
    alarmMgr.setInexactRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
            AlarmManager.INTERVAL_DAY, alarmIntent);
}


public void setup() {
    br = new BroadcastReceiver() {
        @Override
        public void onReceive(Context c, Intent i) {
            Toast.makeText(c, "Rise and Shine!", Toast.LENGTH_LONG).show();
            //Invoke the service here Put the wake lock and initiate bind service

        }
    };
    registerReceiver(br, new IntentFilter("com.testrtc") );
    alarmIntent = PendingIntent.getBroadcast( this, 0, new Intent("com.testrtc"),
            0 );
    alarmMgr = (AlarmManager)(this.getSystemService( Context.ALARM_SERVICE ));
}

list :

   <uses-permission android:name="android.permission.WAKE_LOCK" />

但是我没有收到任何错误，但警报(Toast 消息)不会触发。

EDIT 来自开发者文档:

RTC 示例

这里有一些使用 RTC_WAKEUP 的例子。

大约在下午 2:00 唤醒设备以触发警报，并且每天同一时间重复一次:

// Set the alarm to start at approximately 2:00 p.m.
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.set(Calendar.HOUR_OF_DAY, 14);

// With setInexactRepeating(), you have to use one of the AlarmManager interval
// constants--in this case, AlarmManager.INTERVAL_DAY.
alarmMgr.setInexactRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
        AlarmManager.INTERVAL_DAY, alarmIntent);

这个用于设置重复，说如果我想让我的闹钟在 8:30 响起，然后每 20 分钟重复一次，但是我只想在特定时间触发我的闹钟，但我不想重复。

在早上 8 点 30 分准时唤醒设备触发警报，此后每 20 分钟触发一次:

private AlarmManager alarmMgr;
private PendingIntent alarmIntent;
...
alarmMgr = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(context, AlarmReceiver.class);
alarmIntent = PendingIntent.getBroadcast(context, 0, intent, 0);

// Set the alarm to start at 8:30 a.m.
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.set(Calendar.HOUR_OF_DAY, 8);
calendar.set(Calendar.MINUTE, 30);

// setRepeating() lets you specify a precise custom interval--in this case,
// 20 minutes.
alarmMgr.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
        1000 * 60 * 20, alarmIntent);

Answer 1

确定您的警报需要多精确

选择警报类型通常是创建警报的第一步。另一个区别是您需要警报的精确度。对于大多数应用程序，setInexactRepeating() 是正确的选择。当您使用此方法时，Android 会同步多个不精确重复的警报并同时触发它们。这减少了电池的消耗。

对于像您这样具有严格时间要求的罕见应用，闹钟需要在下午 4:00 精确触发。每天然后使用 setRepeating()。

引用:Decide how precise your alarm needs to be

解决方案:

    alarmMgr = (AlarmManager)getApplicationContext().getSystemService(Context.ALARM_SERVICE);
// Set the alarm to start at approximately 4:00 p.m.
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.set(Calendar.HOUR_OF_DAY, 16);
alarmMgr.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
        1000*60*60*24, alarmIntent);

编辑测试: (每 10 秒触发一次警报)

        alarmMgr = (AlarmManager)getApplicationContext().getSystemService(Context.ALARM_SERVICE);
alarmMgr.setRepeating(AlarmManager.RTC_WAKEUP, SystemClock.elapsedRealtime(),
        1000*10, alarmIntent);

结论:

setup() 处理告警前没有调用方法

---

API 19+ 更新

针对 API 级别 19 或更高级别时，setRepeating 不准确。对于精确重复，您现在可以使用 setExact() 并自行管理重复。

引用:AlarmManager documentation