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当我创建MaterialDatePicker它时，它会选择我指定的日期的前一个日期，而不是指定的日期：

您可以看到 EditText 有 May 12, 2019 但 DatePicker 显示为 May 11, 2019

您可以看到 EditText 有 May 12, 2019 但 DatePicker 显示为 May 11, 2019

openDatePicker 的代码是：

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    binding = ActivityMainBinding.inflate(getLayoutInflater());
    setContentView(binding.getRoot());

    setSupportActionBar(binding.toolbar);

    String dateText = "May 12, 2019";
    binding.etDate.setText(dateText);
    try {
        Date date = new SimpleDateFormat("MMM dd, yyyy").parse(dateText);
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        binding.etDate.setTag(cal);
    } catch (ParseException e) {
        e.printStackTrace();
    }
    binding.etDate.setOnClickListener(v -> {
        Calendar defaultCal = Calendar.getInstance();
        if (binding.etDate.getTag() != null) {
            defaultCal = (Calendar) binding.etDate.getTag();
        }
        openDatePicker(binding.etDate, defaultCal, createDatePickerConstraints(defaultCal, null, null));
    });
}

private void openDatePicker(final EditText tv, Calendar defaultDate, CalendarConstraints constraints) {
    try {
        MaterialDatePicker.Builder<Long> builder = MaterialDatePicker.Builder.datePicker();
        builder.setCalendarConstraints(constraints);
        builder.setSelection(defaultDate.getTimeInMillis());
        MaterialDatePicker<Long> datePicker = builder.build();
        datePicker.addOnPositiveButtonClickListener(selection -> {
            Calendar selectedCalObj = Calendar.getInstance();
            selectedCalObj.setTimeInMillis((long) selection);
            SimpleDateFormat dateFormat = new SimpleDateFormat("MMM d, yyyy", Locale.ENGLISH);
            dateFormat.setTimeZone(TimeZone.getDefault());
            String date = dateFormat.format(selectedCalObj.getTime())
                    .replace("a.m.", "AM")
                    .replace("p.m.", "PM")
                    .replace("am", "AM")
                    .replace("pm", "PM");;
            tv.setText(date);
            tv.setTag(selectedCalObj);
        });
        datePicker.addOnNegativeButtonClickListener(view -> {
            Log.d(TAG, "Cancelled");
        });
        datePicker.show(getSupportFragmentManager(), TAG);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

// helper function to give the constraints:
private CalendarConstraints createDatePickerConstraints(final Calendar entry, final Calendar start, final Calendar end) {
    CalendarConstraints.Builder constraintsBuilder = new CalendarConstraints.Builder();
    if (entry != null)
        constraintsBuilder.setOpenAt(entry.getTimeInMillis());
    if (start != null) {
        constraintsBuilder.setStart(start.getTimeInMillis());
        constraintsBuilder.setValidator(DateValidatorPointForward.from(start.getTimeInMillis()));
    }
    if (end != null) {
        constraintsBuilder.setEnd(end.getTimeInMillis());
        constraintsBuilder.setValidator(DateValidatorPointBackward.before(end.getTimeInMillis()));
    }
    return constraintsBuilder.build();
}

我知道的可能方法是通过将EditText binding.etDate.setTagat偏移onCreate 到我所在的当前时区来修复（因为问题是 2019 年 5 月 12 日 0:00:00 这可能是 DatePicker 选择上一个日期的问题打开），但如果有更好的方法来做到这一点，这将非常有帮助，因为这似乎是一个更常见的代码，在任何地方都很有用，这样我就可以将它作为一个库并在我的主要应用。

任何帮助，将不胜感激。

4

2 回答 2

0

builder.setSelection(defaultDate.getTimeInMillis());

您必须像这样添加当前时间的偏移量

builder.setSelection(defaultDate.getTimeInMillis() + TimeZone.getDefault().getOffset(defaultDate.getTimeInMillis()));

于 2021-08-05T09:01:02.070 回答
0

因此，在经历了大量 GitHub 问题之后，我发现MaterialDatePicker只有 UTC 时间的 getter 和 setter，所以偏移值不是一个好主意，所以将当前时间作为 UTC 传递给它，例如：Link for convert current时区到 UTC

我的示例代码：

try { 
    SimpleDateFormat fromDate = new SimpleDateFromat("MMM dd, yyyy");
    fromDate.setTimeZone(TimeZone.getTimeZone("UTC"));
    Date date = fromDate.parse(inputDateString);
    Calendar cal = Calendar.getInstance(Locale.getDefault());
    cal.setTime(date);
    binding.etDate.setTag(cal);
} catch (ParseException e) {
    e.printStackTrace();
}

我将使用EditText后面的标签来填充我的CalendarConstraints和后面的。MaterialDatePickersetSelection

希望这有帮助！

于 2021-08-05T13:42:53.173 回答