java - DatepickerDialog 不在 Textview 中添加日期

Question

我有个问题。我在 Android Studio 中创建了一个 DatePickerDialog，但是当显示 Datepickerdialog 并且我想添加一个日期时，它不起作用。当我按下按钮并因此更改日期时，我希望看到 DialogPicker，但文本视图中没有出现任何内容。我的代码在这里。如果有人告诉我如何按月、日、年的顺序制作日期也很好

片段类：

公共类片段扩展片段实现 DatePickerDialog.OnDateSetListener {

@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    calendar = Calendar.getInstance();
    Button button = (Button) getView().findViewById(R.id.change);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            DialogFragment datepicker = new DatePickerFragment();
            datepicker.show(getFragmentManager(),  "date picker");
        }
    });
}


@Override
public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
    Calendar c = Calendar.getInstance();
    c.set(Calendar.YEAR, year);
    c.set(Calendar.MONTH, month);
    c.set(Calendar.DAY_OF_MONTH, dayOfMonth);
    String currentime = DateFormat.getDateInstance(DateFormat.FULL).format(calendar.getTime());
    TextView textView = getView().findViewById(R.id.date);
    textView.setText(currentime);
}

}

DatePicker 的类： public class DatePickerFragment extends DialogFragment {

@NonNull
@Override
public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
    Calendar calendar = Calendar.getInstance();
    int year = calendar.get(Calendar.YEAR);
    int month = calendar.get(Calendar.MONTH);
    int day = calendar.get(Calendar.DAY_OF_MONTH);
    return new DatePickerDialog(getActivity(),(DatePickerDialog.OnDateSetListener) getTargetFragment(),
            year, month, day);
}

}

标签： javaandroidandroid-studiodatepicker

Answer 1

fragment_main.xml

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    orientation="Vertical"
    tools:context=".MainFragment">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:hint="Date"
        android:id="@+id/Date"
        android:layout_marginTop="50dp"
        android:layout_centerHorizontal="true"
        android:textSize="30sp"/>

        <Button
        android:id="@+id/tvDate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:hint="Select Date"
        />
    </LinearLayout>

MainFragment.java

public class MainFragment extends Fragment {
    private static final String TAG = "MainFragment";

    private TextView date;
    private Button mDisplayDate;
    private DatePickerDialog.OnDateSetListener mDateSetListener;

   @Nullable
   @Override
   public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
      View view = inflater.inflate(R.layout.fragment, container, false);

    mDisplayDate=view.findViewById(R.id.tvDate);
    date=view.findViewById(R.id.Date);
    mDisplayDate.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Calendar cal = Calendar.getInstance();
            int year = cal.get(Calendar.YEAR);
            int month = cal.get(Calendar.MONTH);
            int day = cal.get(Calendar.DAY_OF_MONTH);

            DatePickerDialog dialog = new DatePickerDialog(
                    MainActivity.this,
                    android.R.style.Theme_Holo_Light_Dialog_MinWidth,
                    mDateSetListener,
                    year,month,day);
            dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
            dialog.show();
        }
    });

    mDateSetListener = new DatePickerDialog.OnDateSetListener() {
        @Override
        public void onDateSet(DatePicker datePicker, int year, int month, int day) {
            month = month + 1;
            Log.d(TAG, "onDateSet: mm/dd/yyy: " + month + "/" + day + "/" + year);

            String date = month + "/" + day + "/" + year;
            date.setText(date);
        }
    };



  return view;
   }
}