Question

我正在制作一个使用AlarmManager和广播接收器的应用程序，每天上午8:20生成通知。

我面临的一个问题是，每次我在上午8:20之后打开应用程序时，都会生成通知。

我想这是因为我用onCreate()方法调用了接收器有没有办法确保接收器只注册一次？

这是我的代码：

public class MainActivity extends AppCompatActivity
{

    AlarmManager alarmManager;
    private PendingIntent alarmIntent;

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


        alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);

        Intent intent = new Intent(this, AlarmReceiver.class);
        alarmIntent = PendingIntent.getBroadcast(MainActivity.this, 0, intent, 0);

        Calendar calendar = Calendar.getInstance();
        calendar.setTimeInMillis(System.currentTimeMillis());
        calendar.set(Calendar.HOUR_OF_DAY, 00);
        calendar.set(Calendar.MINUTE,30);
        alarmManager.setInexactRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), AlarmManager.INTERVAL_DAY, alarmIntent);
 }

public class AlarmReceiver extends BroadcastReceiver
{
    @Override
    public void onReceive(Context context, Intent intent)
    {
        Toast.makeText(context,"Alarm Raised",Toast.LENGTH_SHORT).show();
        NotificationManager notificationManager = (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);
        Intent intent1 = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
        PendingIntent pendingIntent=PendingIntent.getActivity(context,0,intent1,0);
        NotificationCompat.Builder builder = new NotificationCompat.Builder(context);
        builder.setSmallIcon(R.drawable.ic_account_circle_black_18dp);
        builder.setContentTitle("Tracker");
        builder.setContentText("Turn on Gps");
        builder.setPriority(Notification.PRIORITY_MAX);
        builder.setDefaults(Notification.DEFAULT_SOUND);
        builder.setLights(0x0000FF,3000,2000);
        builder.setContentIntent(pendingIntent);
        notificationManager.notify(56, builder.build());
    }
}

Answer 1

setInexactRepeating的第二个参数表示AlarmManager应何时开始其任务。因此，如果你过去给它一个时间，它会立即触发一次。您必须检查calendar.getTimeInMillis（）是否在此之前，如果是，则为其添加一天。

所以你应该简单地改变代码的这一部分

alarmManager.setInexactRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), AlarmManager.INTERVAL_DAY, alarmIntent);

到此：

long timeToStart = calendar.getTimeInMillis();
if(System.currentTimeMillis() < timeToStart){
    timeToStart += 24 * 60 * 60 * 1000; // one day
}
alarmManager.setInexactRepeating(AlarmManager.RTC_WAKEUP, timeToStart, AlarmManager.INTERVAL_DAY, alarmIntent);

AlarmManager广播接收器

1 个答案: