DatePickerDialog 重置 Android 中的日期

Question

我在我的应用程序中使用datePickerDialog。我已将 当前日期 和 onClickListener 都设置在同一个 textView

最初 textView 显示当前日期，当它监听点击事件时，它显示一个DatePickerDialog

我的问题是什么？

当我点击textView 时，它会显示带有当前日期 的DatePicker，然后我设置任何日期，新日期现在在 textView 上可见 但 每次我点击 textView 它在datePickerDialog 中显示当前日期，我希望datepicker 也更新 datePickerDialog 上的日期。

这是我的Activity.javasn-p

final Calendar c = Calendar.getInstance();
mYear = c.get(Calendar.YEAR);
mMonth = c.get(Calendar.MONTH);
mDay = c.get(Calendar.DAY_OF_MONTH);

//format of the current date
String currDate = new SimpleDateFormat("MM/dd/yyyy").format(new Date());

//set current date on textView
dateView = (TextView) findViewById(R.id.date_view);
dateView.setText(currDate);

dateView.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        DatePickerDialog dpd = new DatePickerDialog(TRTimeReminder.this,
                new DatePickerDialog.OnDateSetListener() {
                    @Override
                    public void onDateSet(DatePicker view, int year, int month, int day) {
                        c.set(year, month, day);
                        String date = new SimpleDateFormat("MM/dd/yyyy").format(c.getTime());
                        dateView.setText(date);
                    }
                }, mYear, mMonth, mDay);
            dpd.show();
        }
    });

编辑

我还将DatePickerDialog(TRTimeReminder.this,.....,mYear, mMonth, mDay) 更新为DatePickerDialog(TRTimeReminder.this,....., y, m, d)

其中int y, m, d 是我在onDateSet() 方法中定义为y = year, m = month, d = day 的变量，但是当我点击textView 时它显示初始化日期JAN 1 1900

Answer 1

据我所知，您正在使用 mYear, mMonth, mDay 初始化 dpd，而您永远不会更新这些内容。

关于评论的更新：

在初始化新的DatePickerDialog 时从Calendar c 中提取数据，而不是使用存储的值。

DatePickerDialog dpd = new DatePickerDialog(TRTimeReminder.this,
  new DatePickerDialog.OnDateSetListener() {
        @Override
        Public void onDateSet(DatePicker view, int year, int month, int day) {
        c.set(year, month, day);
        String date = new SimpleDateFormat("MM/dd/yyyy").format(c.getTime());
        dateView.setText(date);
        }

        c.get(Calender.YEAR); // I forgot if you need the ; here when using Java
        c.get(Calender.MONTH;
        c.get(Calender.DAY_OF_MONTH);
}); 

Answer 2

我认为您的代码没有优化或正确有几个原因：

1. 每个点击事件都有一个新的日期选择器实例。
2. 我认为您甚至都没有放弃以前的日期选择器，即使这样，这段代码的状态也很糟糕。
3. 设置当前日期后，您永远不会使用新值重新初始化成员变量 mYear、mMonth、mDay。

修复你的代码 -

DatePickerDialog dpd = new DatePickerDialog(TRTimeReminder.this,
  new DatePickerDialog.OnDateSetListener() {
        @Override
        Public void onDateSet(DatePicker view, int year, int month, int day) {
            mYear = year;
            mMonth = month;
            mDay = day;
           // Perform your operation
        }

}, mYear, mMonth, mDay);

根据我的建议，我更喜欢实现以下代码：-

public class CustomDatePicker extends DialogFragment implements DatePickerDialog.OnDateSetListener {

    private static final String CUSTOM_DIALOG_TAG="custom_dialog";

    public static void showDialog(FragmentManager fm){
        FragmentTransaction ft = fm.beginTransaction();
        CustomDatePicker mPrveInstance = (CustomDatePicker)fm.findFragmentByTag(CUSTOM_DIALOG_TAG);
        if (mPrveInstance != null) {
            ft.remove(mPrveInstance);
        }
        ft.addToBackStack(null);
        // Create and show the dialog.
        CustomDatePicker datePicker = new CustomDatePicker();
        datePicker.show(ft, CUSTOM_DIALOG_TAG);
    }
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // Use the current date as the default date in the picker
        final Calendar c = Calendar.getInstance();
        int year = c.get(Calendar.YEAR);
        int month = c.get(Calendar.MONTH);
        int day = c.get(Calendar.DAY_OF_MONTH);

        // Create a new instance of DatePickerDialog and return it
        return new DatePickerDialog(getActivity(), this, year, month, day);
    }

    @Override
    public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
        // Create Interface and send callback to activity to call show
        // Avoid exposing dialog fragment instance to activity
        Calendar.getInstance().set(year, month, day);
    }

}

只要你想显示，就直接从Activity调用show方法。

// CustomDatePicker.showDialog(getFragmentManager());

Answer 3

在用户设置日期后调用 OnDateSet。如果要在对话框中显示上一个日期，您必须首先调用 onCreateDialog 并设置日期。请参见下面的代码示例：

@Override
public Dialog onCreateDialog(Bundle savedInstanceState)
{
int year = 0;
int month = 0;
int day = 0;

// get previous date if available
String dateFormatted = dateView.getText();
Log.i(TAG, "What is the user's date " + dateFormatted);

if (dateFormatted == null || dateFormatted.isEmpty())
{
  // Use the current date as the default date in the picker
  final Calendar c = Calendar.getInstance();
  year = c.get(Calendar.YEAR);
  Log.i(TAG, "what is the phone's year: " + year);
  month = c.get(Calendar.MONTH);
  Log.i(TAG, "what is the phone's month: " + month);
  day = c.get(Calendar.DAY_OF_MONTH);
  Log.i(TAG, "what is the phone's day: " + day);
} else
{
  day = Integer.parseInt(dateFormatted.substring(0, 2));
  Log.i(TAG, "what is the user's day: " + day);
  month = Integer.parseInt(dateFormatted.substring(3, 5));
  // Correct month to 0-11 format from 1-12 format
  month = month - 1;
  Log.i(TAG, "what is the user's month: " + month);
  year = Integer.parseInt(dateFormatted.substring(6, 10));
  Log.i(TAG, "what is the user's year: " + year);
}

// Create a new instance of DatePickerDialog and return it
return new DatePickerDialog(getActivity(), this, year, month, day);
}

注意我正在使用实现 DatePickerDialog.OnDateSetListener 的 DialogFragment。因此，您可能需要将 getActivity 更改为此。我想它会起作用。

然后使用onDateSet：

public void onDateSet(DatePicker view, int year, int month, int day)
{
// Do something with the date chosen by the user
Time time = new Time();
time.set(day, month, year);
String date = time.format("%d-%m-%Y");
Log.i(TAG, "The date you are setting: " + date);
dateView.setText(date);
Log.i(TAG, "You have set the date to: " + date);
}

Answer 4

在取消点击时重置日期选择器：

1. 在日期选择器上添加 onDismissListner
2. 在 onDismissListener 内部，调用 updateData 方法

例子：

datePicker.setOnDismissListener((dialog) -> {
    datePicker.updateData(Year, Month, Date);
}

注意：您可能会认为是用户单击确定此代码会出现问题。理想情况下不会。当您在 onDateSet 中调用 updateData 时，您不会遇到任何问题。

参考：https://stackoverflow.com/a/57703547/1994950