Question

正如标题所暗示的那样，我希望安排一项任务在某些特定时间运行。例如，我可能会在每周二和周四的5:00运行它。我见过several scheduling methods for Android，但所有这些似乎都是以“延迟后执行任务”或“每n秒执行任务”的形式运行。

现在我可以通过计算执行任务本身期间下次执行的时间来判断它，但这似乎不够优雅。有没有更好的方法来做到这一点？

Answer 1

您需要设置闹钟以执行这些任务。一旦触发警报，很可能最终会调用服务：

private void setAlarmToCheckUpdates() {
        Calendar calendar = Calendar.getInstance();

        if (calendar.get(Calendar.HOUR_OF_DAY)<22){
                calendar.set(Calendar.HOUR_OF_DAY, 22);
        } else {
                calendar.add(Calendar.DAY_OF_YEAR, 1);//tomorrow
                calendar.set(Calendar.HOUR_OF_DAY, 22); //22.00
        }

        Intent myIntent = new Intent(this.getApplicationContext(), ReceiverCheckUpdates.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(this.getApplicationContext(), 0, myIntent,0);
        AlarmManager alarmManager = (AlarmManager)this.getApplicationContext().getSystemService(ALARM_SERVICE);
        alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
    }

但是，如果您需要专门设置一天：

int weekday = calendar.get(Calendar.DAY_OF_WEEK);  
if (weekday!=Calendar.THURSDAY){//if we're not in thursday
    //we calculate how many days till thursday
    //days = The limit of the week (its saturday) minus the actual day of the week, plus how many days till desired day (5: sunday, mon, tue, wed, thur). Modulus of it.
    int days = (Calendar.SATURDAY - weekday + 5) % 7; 
    calendar.add(Calendar.DAY_OF_YEAR, days);
}
//now we just set hour to 22.00 and done.

上面的代码有点棘手和数学。如果你不想做一些愚蠢的事情那么容易：

//dayOfWeekToSet is a constant from the Calendar class
//c is the calendar instance
public static void SetToNextDayOfWeek(int dayOfWeekToSet, Calendar c){
    int currentDayOfWeek = c.get(Calendar.DAY_OF_WEEK);
            //add 1 day to the current day until we get to the day we want
    while(currentDayOfWeek != dayOfWeekToSet){
        c.add(Calendar.DAY_OF_WEEK, 1);
        currentDayOfWeek = c.get(Calendar.DAY_OF_WEEK);
    }
}

在Android中安排一周中特定日期的任务

1 个答案: