android - 同一 Activity 中的多个 DatePickers

Question

我对 Android 平台完全陌生，在学习开发过程的同时一直在构建应用程序。

目前，我正在进行一项 Activity ，我需要在其中部署 2 个日期选择器。一个是“开始日期”，另一个是“结束日期”。我一直在关注 android 开发者页面上的 DatePicker 教程:http://developer.android.com/resources/tutorials/views/hello-datepicker.html

对于一个 DatePicker，它工作得很好。

现在我的问题是，当我为第二个日期选择器复制整个过程时，它在模拟器和手机上都显示得很好。但是无论我按哪个按钮来选择日期，只有第一个 TextView 会更新，而第二个 TextView 会继续显示当前日期。

代码如下:

package com.datepicker;

import java.util.Calendar;

import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TextView;

public class datepicker extends Activity {

private TextView mDateDisplay;
private TextView endDateDisplay;
private Button mPickDate;
private Button endPickDate;
private int mYear;
private int mMonth;
private int mDay;

static final int START_DATE_DIALOG_ID = 0;
static final int END_DATE_DIALOG_ID = 0;


/** Called when the activity is first created. */
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    /*  capture our View elements for the start date function   */
    mDateDisplay = (TextView) findViewById(R.id.startdateDisplay);
    mPickDate = (Button) findViewById(R.id.startpickDate);

    /* add a click listener to the button   */
    mPickDate.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            showDialog(START_DATE_DIALOG_ID);
        }
    });

    /* get the current date */
    final Calendar c = Calendar.getInstance();
    mYear = c.get(Calendar.YEAR);
    mMonth = c.get(Calendar.MONTH);
    mDay = c.get(Calendar.DAY_OF_MONTH);

    /* display the current date (this method is below)  */
    updateStartDisplay();


 /* capture our View elements for the end date function */
    endDateDisplay = (TextView) findViewById(R.id.enddateDisplay);
    endPickDate = (Button) findViewById(R.id.endpickDate);

    /* add a click listener to the button   */
    endPickDate.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            showDialog(END_DATE_DIALOG_ID);
        }
    });

    /* get the current date */
    final Calendar c1 = Calendar.getInstance();
    mYear = c1.get(Calendar.YEAR);
    mMonth = c1.get(Calendar.MONTH);
    mDay = c1.get(Calendar.DAY_OF_MONTH);

    /* display the current date (this method is below)  */
    updateEndDisplay();
}



private void updateEndDisplay() {
    endDateDisplay.setText(
            new StringBuilder()
                // Month is 0 based so add 1
                .append(mMonth + 1).append("-")
                .append(mDay).append("-")
                .append(mYear).append(" "));

}



private void updateStartDisplay() {
    mDateDisplay.setText(
            new StringBuilder()
                // Month is 0 based so add 1
                .append(mMonth + 1).append("-")
                .append(mDay).append("-")
                .append(mYear).append(" "));


}

/* 当用户在开始日期函数的对话框中“设置”日期时收到的回调 */

 private DatePickerDialog.OnDateSetListener mDateSetListener =
            new DatePickerDialog.OnDateSetListener() {

            public void onDateSet(DatePicker view, int year, 
                                  int monthOfYear, int dayOfMonth) {
                mYear = year;
                mMonth = monthOfYear;
                mDay = dayOfMonth;
                updateStartDisplay();
            }
        };

@Override
protected Dialog onCreateDialog(int id) {
    switch (id) {
    case START_DATE_DIALOG_ID:
        return new DatePickerDialog(this,
                    mDateSetListener,
                    mYear, mMonth, mDay);
    }
    return null;
}
/* the callback received when the user "sets" the date in the dialog for the end date function  */

private DatePickerDialog.OnDateSetListener endDateSetListener =
        new DatePickerDialog.OnDateSetListener() {

            public void onDateSet(DatePicker view, int year, 
                                  int monthOfYear, int dayOfMonth) {
                mYear = year;
                mMonth = monthOfYear;
                mDay = dayOfMonth;
                updateStartDisplay();
            }
        };

protected Dialog onCreateDialog1(int id) {
    switch (id) {
    case END_DATE_DIALOG_ID:
        return new DatePickerDialog(this,
                    endDateSetListener,
                    mYear, mMonth, mDay);
    }
    return null;
}

请告知代码所需的更改。

Answer 1

我有一个解决方案，可以在不添加新对话框类型的情况下允许无限数量的日期字段。当用户单击其中一个按钮时，我会在启动 DatePickerDialog 之前注册当前正在修改的 TextView 和 Calendar。对话框的 OnDateSetListener 然后更新注册的 TextView 和日历。

import java.util.Calendar;

import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.app.DatePickerDialog.OnDateSetListener;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TextView;

public class MultiDatePickerActivity extends Activity {

    private TextView startDateDisplay;
    private TextView endDateDisplay;
    private Button startPickDate;
    private Button endPickDate;
    private Calendar startDate;
    private Calendar endDate;

    static final int DATE_DIALOG_ID = 0;

    private TextView activeDateDisplay;
    private Calendar activeDate;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.multidatepicker);

        /*  capture our View elements for the start date function   */
        startDateDisplay = (TextView) findViewById(R.id.startDateDisplay);
        startPickDate = (Button) findViewById(R.id.startPickDate);

        /* get the current date */
        startDate = Calendar.getInstance();

        /* add a click listener to the button   */
        startPickDate.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                showDateDialog(startDateDisplay, startDate);
            }
        });

        /* capture our View elements for the end date function */
        endDateDisplay = (TextView) findViewById(R.id.endDateDisplay);
        endPickDate = (Button) findViewById(R.id.endPickDate);

        /* get the current date */
        endDate = Calendar.getInstance();

        /* add a click listener to the button   */
        endPickDate.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                showDateDialog(endDateDisplay, endDate);
            }
        });

        /* display the current date (this method is below)  */
        updateDisplay(startDateDisplay, startDate);
        updateDisplay(endDateDisplay, endDate);
    }

    private void updateDisplay(TextView dateDisplay, Calendar date) {
        dateDisplay.setText(
                new StringBuilder()
                    // Month is 0 based so add 1
                    .append(date.get(Calendar.MONTH) + 1).append("-")
                    .append(date.get(Calendar.DAY_OF_MONTH)).append("-")
                    .append(date.get(Calendar.YEAR)).append(" "));

    }

    public void showDateDialog(TextView dateDisplay, Calendar date) {
        activeDateDisplay = dateDisplay;
        activeDate = date;
        showDialog(DATE_DIALOG_ID);
    }

    private OnDateSetListener dateSetListener = new OnDateSetListener() {
        @Override
        public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
            activeDate.set(Calendar.YEAR, year);
            activeDate.set(Calendar.MONTH, monthOfYear);
            activeDate.set(Calendar.DAY_OF_MONTH, dayOfMonth);
            updateDisplay(activeDateDisplay, activeDate);
            unregisterDateDisplay();
        }
    };

    private void unregisterDateDisplay() {
        activeDateDisplay = null;
        activeDate = null;
    }

    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id) {
            case DATE_DIALOG_ID:
                return new DatePickerDialog(this, dateSetListener, activeDate.get(Calendar.YEAR), activeDate.get(Calendar.MONTH), activeDate.get(Calendar.DAY_OF_MONTH));
        }
        return null;
    }

    @Override
    protected void onPrepareDialog(int id, Dialog dialog) {
        super.onPrepareDialog(id, dialog);
        switch (id) {
            case DATE_DIALOG_ID:
                ((DatePickerDialog) dialog).updateDate(activeDate.get(Calendar.YEAR), activeDate.get(Calendar.MONTH), activeDate.get(Calendar.DAY_OF_MONTH));
                break;
        }
    }
}

这种灵 active 在您直到运行时才知道需要多少日期选择器的应用程序中很有用。