Question

首先，我想每天自动更改textview文本。例如，第一天文本视图文本是“第一文本”，第二天文本是8点钟的“第二文本”。该文本是永久性的，直到第二天8点。

我尝试使用此代码，但问题是如果用户未在8点打开此页面，则不会触发代码。文本在“mquote数组”里面

 SharedPreferences pref =getApplicationContext().getSharedPreferences("myPrefsKey",Context.MODE_PRIVATE) ; 
    dayCount = pref.getInt("dayCount", 0);


    Calendar cal = Calendar.getInstance();
    int hour=cal.get(Calendar.HOUR_OF_DAY);
    int minute=cal.get(Calendar.MINUTE);        


    if ((hour==8 && minute==1 ))
        updateQuote();


tvQuote.setText(mquote.getQuote(dayCount));

public void updateQuote()
{

        if (dayCount==4)
            dayCount=0;
    dayCount++;
    pref.edit().putInt("dayCount",dayCount).apply();


}

Answer 1

您需要AlarmManager实施：

public class AlarmReceiver extends BroadcastReceiver {

    // The app's AlarmManager, which provides access to the system alarm services.
    private AlarmManager alarmMgr;
    // The pending intent that is triggered when the alarm fires.
    private PendingIntent alarmIntent;

    public void setAlarm(Context context) {

        alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        Intent intent = new Intent(context, AlarmReceiver.class);
        alarmIntent = PendingIntent.getBroadcast(context, 0, intent, 0);
        Calendar calendar = Calendar.getInstance();
        calendar.setTimeInMillis(System.currentTimeMillis());

        // set the Alarm's trigger time to 8:00 a.m.
        calendar.set(Calendar.HOUR_OF_DAT, 9);

        // Set the alarm to fire at approximately 8:30 a.m., according to the device's
        // clock, and to repeat once a day.
        alarmManager.setInexactRepeating(AlarmManager.RTC,  
            calendar.getTimeInMillis(), AlarmManager.INTERVAL_DAY, alarmIntent);

    }

    public void onReceive(Context context, Intent intent) {

        if (intent.getAction().equals("android.intent.action.BOOT_COMPLETED"))
        {
            alarm.setAlarm(context);
        } else if(Objects.equals(intent, alarmIntent)) {
            SharedPreferences pref = getApplicationContext().getSharedPreferences("key", Context.MODE_PRIVATE);
            int dayCount = pref.getInt("dayCount", 0);
            dayCount %= 4;
            pref.edit().putInt("dayCount", ++daysCount).apply();
        }
    }
}

Answer 2

您在偏好设置中上次更新偏好设置时存储的毫秒数：

SharedPreferences pref = getApplicationContext().getSharedPreferences("msKey", Context.MODE_PRIVATE);
msCount = pref.getInt("msCount", 0);

long milliseconds = System.currentTimeMillis();

long diff = milliseconds - msCount;

diff += (8 * 60 * 60 * 1000); // compensating difference for 8'O clock condition

int days = (int) Math.ceil(diff / 24 / 60 / 60 / 1000);

days %= 4; // Because you were resetting days count after 4 increments

updateQuote(days);

public void updateQuote(days) {

    if(days == 0) {
        pref.edit().putInt("msCount", milliseconds).apply();
    }

}

Answer 3

您应该使用时间戳来比较两个日期。试试这段代码。但是在用户使用应用程序时发生了1天，它不会触发。如果你想克服这一点，那么每天使用AlarmManager触发一个事件。

SharedPreferences pref = getApplicationContext().getSharedPreferences("myPrefsKey",Context.MODE_PRIVATE);

lastDay_ms= pref.getInt("time_ms", 0);
Calendar today = Calendar.getInstance();

long diff = today.getTimeInMillis() - lastDay_ms; //result in millis

final long ONE_DAY = 24*60*60*1000; //millis in a day

if (diff > ONE_DAY)
     updateQuote();

每天自动更改textview

3 个答案: