如何在 material-component 的 dateRangePicker 上使用 setSelection？

Question

我想在打开 dateRangePicker 时显示选定的日期范围，我知道 setSelected 方法就是为此而我试过它不起作用，或者我做错了什么，请帮助

这是我已经尝试过的

public void openDateRangePicker(View view) {
 MaterialDatePicker.Builder builder =
                MaterialDatePicker.Builder.dateRangePicker();

        CalendarConstraints.Builder constraintsBuilder = new CalendarConstraints.Builder();

        MaterialDatePicker<Pair<Long,Long>> picker = builder.build();
        builder.setCalendarConstraints(constraintsBuilder.build());

        picker.setStyle(DialogFragment.STYLE_NORMAL, R.style.Custom_MaterialCalendar_Fullscreen);
        if(!firstDateStr.isEmpty() || !endDateStr.isEmpty()){
            builder.setSelection(selectionDates);

        }
        picker.show(getSupportFragmentManager(), picker.toString());



    picker.addOnPositiveButtonClickListener(new MaterialPickerOnPositiveButtonClickListener<Pair<Long, Long>>() {
        @Override
        public void onPositiveButtonClick(Pair<Long, Long> selection) {

            long firstDateLong = selection.first;
            Date firstDate=new Date(firstDateLong);
            long endDateLong = selection.second;
            Date endDate=new Date(endDateLong);

            SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd", Locale.getDefault());

            //format yyyy-MM-dd
            firstDateStr = sdf2.format(firstDate);
            endDateStr = sdf2.format(endDate);
            selectionDates = selection;


            selectedDatesStr = firstDateStr + " to " + endDateStr ;//+ " (" + (daysBetween + 1) + " days)";
            tvDates.setText(selectedDatesStr);
            tvDates.setTypeface(Typeface.DEFAULT_BOLD);
            picker.dismiss();

        }
    }); 

}

我在这里做的是保存选择对象，并在下次打开选择器时用它来显示范围，但是它打开时没有任何选择，就像第一次打开一样！

Answer 1

行的顺序很重要，您需要在完成构建器设置后调用 builder.build();。

  String firstDateStr="";
  String endDateStr="";

Pair<Long, Long> selectionDates=null;
public void openDateRangePicker() {

   MaterialDatePicker.Builder builder =
            MaterialDatePicker.Builder.dateRangePicker();

    CalendarConstraints.Builder constraintsBuilder = new CalendarConstraints.Builder();

    builder.setCalendarConstraints(constraintsBuilder.build());

   // picker.setStyle(DialogFragment.STYLE_NORMAL);
    if(selectionDates!=null){
        builder.setSelection(selectionDates);

    }
    MaterialDatePicker<Pair<Long,Long>> picker = builder.build();
    picker.show(getSupportFragmentManager(), picker.toString());



    picker.addOnPositiveButtonClickListener(new MaterialPickerOnPositiveButtonClickListener<Pair<Long, Long>>() {
        @Override
        public void onPositiveButtonClick(Pair<Long, Long> selection) {

            long firstDateLong = selection.first;
            Date firstDate=new Date(firstDateLong);
            long endDateLong = selection.second;
            Date endDate=new Date(endDateLong);

            SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd", Locale.getDefault());

            //format yyyy-MM-dd
            firstDateStr = sdf2.format(firstDate);
            endDateStr = sdf2.format(endDate);
            selectionDates = selection;


            selectedDatesStr = firstDateStr + " to " + endDateStr ;//+ " (" + (daysBetween + 1) + " days)";
           tvDates.setText(selectedDatesStr);
          tvDates.setTypeface(Typeface.DEFAULT_BOLD);
            picker.dismiss();

        }
    });

}

如何在 material-component 的 dateRangePicker 上使用 setSelection？

how to use setSelection on dateRangePicker of material-component?

java

android

daterangepicker

material-components-android