Android API 21+ DatePicker无法隐藏字段

Question

我试图在 AlertDialog 的 DatePicker 中仅显示日期和月份字段。在 API 21 之前的 API 中，我可以使用代码 below.But 来完成，而我在 API21+ "getDeclaredFields()" 中尝试这样做却不行甚至 returns 像 "mYearPicker" 或 "mYearSpinner" fields.Does 任何人都知道我怎样才能显示日期和月份字段？我什至不知道字段“116”是什么.

我的代码是这样的：

 final DatePicker datePickerStart = new DatePicker(new ContextThemeWrapper(getActivity(), android.R.style.Theme_Holo_Light_Dialog_NoActionBar));
    datePickerStart .setCalendarViewShown(false);
    datePickerStart .setSpinnersShown(true);
    try {
        Field f[] = datePickerStart .getClass().getDeclaredFields();
        for (Field field : f) {
            if (field.getName().equals("mYearPicker")|| field.getName().equals("mYearSpinner")) {
                field.setAccessible(true);
                Object yearPicker = new Object();
                yearPicker = field.get(datePickerStart);
                ((View) yearPicker).setVisibility(View.GONE);
            }
        }
    }
    catch (Exception e) {
        Log.e("ERROR", e.getMessage());
    }

应该看起来像： Before API 21

看起来像这样： API 21+

有什么想法吗？

Answer 1

感谢@Morse，我找到了解决方案

public DatePicker initMonthPicker(){
    DatePicker dp_mes = new DatePicker(new ContextThemeWrapper(getActivity(), android.R.style.Theme_Holo_Light_Dialog_NoActionBar));

    int year    = dp_mes.getYear();
    int month   = dp_mes.getMonth();
    int day     = dp_mes.getDayOfMonth();

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP){
        int daySpinnerId = Resources.getSystem().getIdentifier("day", "id", "android");
        if (daySpinnerId != 0)
        {
            View daySpinner = dp_mes.findViewById(daySpinnerId);
            if (daySpinner != null)
            {
                daySpinner.setVisibility(View.VISIBLE);
            }
        }

        int monthSpinnerId = Resources.getSystem().getIdentifier("month", "id", "android");
        if (monthSpinnerId != 0)
        {
            View monthSpinner = dp_mes.findViewById(monthSpinnerId);
            if (monthSpinner != null)
            {
                monthSpinner.setVisibility(View.VISIBLE);
            }
        }

        int yearSpinnerId = Resources.getSystem().getIdentifier("year", "id", "android");
        if (yearSpinnerId != 0)
        {
            View yearSpinner = dp_mes.findViewById(yearSpinnerId);
            if (yearSpinner != null)
            {
                yearSpinner.setVisibility(View.GONE);
            }
        }
    } else { //Older SDK versions
        Field f[] = dp_mes.getClass().getDeclaredFields();
        for (Field field : f)
        {
            if(field.getName().equals("mDayPicker") || field.getName().equals("mDaySpinner"))
            {
                field.setAccessible(true);
                Object dayPicker = null;
                try {
                    dayPicker = field.get(dp_mes);
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
                ((View) dayPicker).setVisibility(View.GONE);
            }

            if(field.getName().equals("mMonthPicker") || field.getName().equals("mMonthSpinner"))
            {
                field.setAccessible(true);
                Object monthPicker = null;
                try {
                    monthPicker = field.get(dp_mes);
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
                ((View) monthPicker).setVisibility(View.VISIBLE);
            }

            if(field.getName().equals("mYearPicker") || field.getName().equals("mYearSpinner"))
            {
                field.setAccessible(true);
                Object yearPicker = null;
                try {
                    yearPicker = field.get(dp_mes);
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
                ((View) yearPicker).setVisibility(View.GONE);
            }
        }
    }
    return dp_mes;
}

所以我只是在需要一个新的 DatePicker 对象时调用这个方法

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