警报管理器延迟报警响铃的问题

Question

我遇到了一个问题，当我设置一个时间时，警报响起有延迟。有时警报也会提前发生。我不确定我做错了什么。希望有人可以帮我解决这个问题。

public void showHourPicker(View view) {


    currentHour = calendar.get(Calendar.HOUR_OF_DAY);
    currentMinute = calendar.get(Calendar.MINUTE);

    timePickerDialog = new TimePickerDialog(MainActivity.this, android.R.style.Theme_Holo_Light_Dialog_NoActionBar, new TimePickerDialog.OnTimeSetListener() {
        @Override
        public void onTimeSet(TimePicker timePicker, int hourOfDay, int minutes) {

            if (hourOfDay >= 12) {
                amPm = "PM";
            } else {
                amPm = "AM";
            }
            txtTime.setText(String.format("%02d:%02d ", hourOfDay, minutes) + amPm);

            calendar.set(Calendar.HOUR_OF_DAY,hourOfDay);
            calendar.set(Calendar.MINUTE,minutes);
        }

    }, currentHour, currentMinute, false);

    timePickerDialog.setTitle(" Your Expected Time : " + exp.getText());
    timePickerDialog.getWindow().setBackgroundDrawableResource(android.R.color.transparent);
    timePickerDialog.show();

    startAlarm(calendar);

}

public void startAlarm(Calendar calendar) {

    AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
    Intent intent = new Intent(this, MyBroadcastReceiver.class);
    PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, intent, 0);
    alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,calendar.getTimeInMillis(),AlarmManager.INTERVAL_DAY,pendingIntent);

}

Answer 1

这是AlarmManager.setRepeating中描述的预期行为：

从API 19开始，所有重复警报都不准确。如果您的应用程序需要精确的交付时间，那么它必须使用一次性精确警报，每次重新安排如上所述。