检测现有警报

Question

我使用此功能创建闹钟，如果已经创建闹钟，它将取消闹钟，如果没有，则创建闹钟

但它不起作用，alarmUp永远不会错误

如何检查警报是否存在？

public void alarm(int hour, int minutes)
{
        Intent intent = new Intent(getApplicationContext(),AlarmActivity.class);
        PendingIntent sender = PendingIntent.getActivity(getApplicationContext(), 0, intent, 0);

        Calendar calendar = Calendar.getInstance();
        calendar.set(Calendar.HOUR, 24);
        calendar.set(Calendar.HOUR_OF_DAY, hour);
        calendar.set(Calendar.MINUTE, minutes);
        calendar.set(Calendar.SECOND, 0);
        boolean alarmUp = (PendingIntent.getActivity(getApplicationContext(), 0, intent, PendingIntent.FLAG_NO_CREATE) != null);

        AlarmManager am = (AlarmManager) getApplicationContext().getSystemService(getApplicationContext().ALARM_SERVICE);
        if(!alarmUp)
        {
            am.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), sender);
        }
        else
        {
            am.cancel(sender);
        }
}

Answer 1

你有正确的想法，但顺序错了。你需要这样做：

boolean alarmUp = (PendingIntent.getActivity(getApplicationContext(), 0, intent, PendingIntent.FLAG_NO_CREATE) != null);

在你这样做之前：

PendingIntent sender = PendingIntent.getActivity(getApplicationContext(), 0, intent, 0);

alarmUp始终为真的原因是因为您之前刚刚创建了PendingIntent！