java - Android DataPickerDialog onDateChanged 未触发

Question

我在按照 Android 教程中的步骤操作 DatePickerDialog 时遇到问题。

链接 TextView 以在获得焦点时启动 DatePickerDialog，如下所示:

EditText fNac = (EditText)findViewById(R.id.regFecha);
            fNac.setonfocusChangeListener(new View.onfocusChangeListener(){

                    @Override
                    public void onfocusChange(View v, boolean hasFocus) {
                            // TODO Auto-generated method stub
                            // Desde aquí lanzamos el datepicker
                            if (hasFocus){
                                    DialogFragment newFragment = new DatePickerFragment();
                                    newFragment.show(getSupportFragmentManager() , "datePicker");
                            }
                    }

工作正常，DatePickerDialog 已启动。我实例化了一个以这种方式创建的新 DatePickerFragment 类:

import java.util.Calendar;

import android.app.DatePickerDialog;
import android.app.Dialog;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.util.Log;
import android.widget.DatePicker;

public class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener {

    private DatePickerDialog mDatePickerDialog;

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState){
            // Usamos la fecha actual como primera fecha a mostrar
            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);

            // Devolvemos la instancia de un Dialog con la fecha actual
            mDatePickerDialog = new DatePickerDialog(getActivity(),this,year,month,day);
            return mDatePickerDialog;
    }

    @Override
    public void onDateSet(DatePicker view, int year, int month, int day) {
            // TODO Auto-generated method stub
            Log.v("LOG_CAT","OK");
    }

    public void onDateChanged(DatePicker view, int year, int monthOfYear,
                    int dayOfMonth) {
            // TODO Auto-generated method stub
            Log.v("LOG_CAT", "Ok2");
    }

这就是问题所在。我想使用 onDateChanged 方法更改对话框的标题，但从未调用过。我尝试创建一个 onDateChangedListener，但 DatePickerDialog 没有。

我该怎么做？

提前致谢。

Answer 1

只需扩展 DatePickerDialog 类并重写 onDateChanged，如下所示。我包含了一个新的构造函数，它接受一个 Calendar 对象并自行设置年、月和日，从而避免了不必要的输入。 (我不明白为什么这还不是一个选项。)无论如何，这里是如何使用类和更短的构造函数:

public class DatePickerFragment extends DialogFragment implements OnDateSetListener {
    public class MyDatePickerDialog extends DatePickerDialog {
        private Calendar calendar;
        private final String format = "EEEE, MMMM dd, yyyy";

        // Regular constructor
        public MyDatePickerDialog(Context context, OnDateSetListener callBack, int year, int monthOfYear, int dayOfMonth) {
            super(context, callBack, year, monthOfYear, dayOfMonth);
            calendar = Calendar.getInstance();
        }

        // Short constructor
        public MyDatePickerDialog(Context context, OnDateSetListener callBack, Calendar calendar) {
            super(context, callBack, calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH), calendar.get(Calendar.DAY_OF_MONTH));
            this.calendar = calendar;
        }

        @Override
        public void onDateChanged(DatePicker view, int year, int month, int day) {
            super.onDateChanged(view, year, month, day);
            calendar.set(year, month, day);
            setTitle(DateFormat.format(format, calendar));
        }
    }

    private MyDatePickerDialog mDatePickerDialog;

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        mDatePickerDialog = new MyDatePickerDialog(this, this, Calendar.getInstance());
        return mDatePickerDialog;
    }

    @Override
    public void onDateSet(DatePicker view, int year, int month, int day) {
        Log.v("DatePickerFragment", "onDateSet");
    }
}