安卓开发中的双日期选择控件（可隐藏日，只显示年月）

在安卓开发中，会碰到选开始日期和结束日期的问题。特别是在使用Pad时，如果弹出一个Dialog，能够同时选择开始日期和结束日期，那将是极好的。我在开发中在DatePickerDialog的基础上做了修改，实现了这种Dialog。效果如下：

具体实现方法为：

先新建一个安卓项目DoubleDatePicker，在res/layout文件夹下新建date_picker_dialog.xml，内容如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center_horizontal"
    android:orientation="horizontal"
    android:paddingTop="10dp" >

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:orientation="vertical"
        android:padding="5dip" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="开始日期" />

        <DatePicker
            android:id="@+id/datePickerStart"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:calendarViewShown="false" />
    </LinearLayout>

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="fill_parent"
        android:src="@drawable/fenge" />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:orientation="vertical"
        android:padding="5dip" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="结束日期" />

        <DatePicker
            android:id="@+id/datePickerEnd"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:calendarViewShown="false" />
    </LinearLayout>

</LinearLayout>

然后，在src的 默认包下新建文件DoubleDatePickerDialog.java，内容如下：

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.doubledatepicker;

import java.lang.reflect.Field;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.DatePicker;
import android.widget.DatePicker.OnDateChangedListener;

/**
 * A simple dialog containing an {@link android.widget.DatePicker}.
 *
 * <p>
 * See the <a href="{@docRoot}guide/topics/ui/controls/pickers.html">Pickers</a>
 * guide.
 * </p>
 */
public class DoubleDatePickerDialog extends AlertDialog implements OnClickListener, OnDateChangedListener {

    private static final String START_YEAR = "start_year";
    private static final String END_YEAR = "end_year";
    private static final String START_MONTH = "start_month";
    private static final String END_MONTH = "end_month";
    private static final String START_DAY = "start_day";
    private static final String END_DAY = "end_day";

    private final DatePicker mDatePicker_start;
    private final DatePicker mDatePicker_end;
    private final OnDateSetListener mCallBack;

    /**
     * The callback used to indicate the user is done filling in the date.
     */
    public interface OnDateSetListener {

        /**
         * @param view
         *            The view associated with this listener.
         * @param year
         *            The year that was set.
         * @param monthOfYear
         *            The month that was set (0-11) for compatibility with
         *            {@link java.util.Calendar}.
         * @param dayOfMonth
         *            The day of the month that was set.
         */
        void onDateSet(DatePicker startDatePicker, int startYear, int startMonthOfYear, int startDayOfMonth,
                DatePicker endDatePicker, int endYear, int endMonthOfYear, int endDayOfMonth);
    }

    /**
     * @param context
     *            The context the dialog is to run in.
     * @param callBack
     *            How the parent is notified that the date is set.
     * @param year
     *            The initial year of the dialog.
     * @param monthOfYear
     *            The initial month of the dialog.
     * @param dayOfMonth
     *            The initial day of the dialog.
     */
    public DoubleDatePickerDialog(Context context, OnDateSetListener callBack, int year, int monthOfYear, int dayOfMonth) {
        this(context, 0, callBack, year, monthOfYear, dayOfMonth);
    }

    public DoubleDatePickerDialog(Context context, int theme, OnDateSetListener callBack, int year, int monthOfYear,
            int dayOfMonth) {
        this(context, 0, callBack, year, monthOfYear, dayOfMonth, true);
    }

    /**
     * @param context
     *            The context the dialog is to run in.
     * @param theme
     *            the theme to apply to this dialog
     * @param callBack
     *            How the parent is notified that the date is set.
     * @param year
     *            The initial year of the dialog.
     * @param monthOfYear
     *            The initial month of the dialog.
     * @param dayOfMonth
     *            The initial day of the dialog.
     */
    public DoubleDatePickerDialog(Context context, int theme, OnDateSetListener callBack, int year, int monthOfYear,
            int dayOfMonth, boolean isDayVisible) {
        super(context, theme);

        mCallBack = callBack;

        Context themeContext = getContext();
        setButton(BUTTON_POSITIVE, "确 定", this);
        setButton(BUTTON_NEGATIVE, "取 消", this);
        // setButton(BUTTON_POSITIVE,
        // themeContext.getText(android.R.string.date_time_done), this);
        setIcon(0);

        LayoutInflater inflater = (LayoutInflater) themeContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view = inflater.inflate(R.layout.date_picker_dialog, null);
        setView(view);
        mDatePicker_start = (DatePicker) view.findViewById(R.id.datePickerStart);
        mDatePicker_end = (DatePicker) view.findViewById(R.id.datePickerEnd);
        mDatePicker_start.init(year, monthOfYear, dayOfMonth, this);
        mDatePicker_end.init(year, monthOfYear, dayOfMonth, this);
        // updateTitle(year, monthOfYear, dayOfMonth);

        // 如果要隐藏当前日期，则使用下面方法。
        if (!isDayVisible) {
            hidDay(mDatePicker_start);
            hidDay(mDatePicker_end);
        }
    }

    /**
     * 隐藏DatePicker中的日期显示
     * 
     * @param mDatePicker
     */
    private void hidDay(DatePicker mDatePicker) {
        Field[] datePickerfFields = mDatePicker.getClass().getDeclaredFields();
        for (Field datePickerField : datePickerfFields) {
            if ("mDaySpinner".equals(datePickerField.getName())) {
                datePickerField.setAccessible(true);
                Object dayPicker = new Object();
                try {
                    dayPicker = datePickerField.get(mDatePicker);
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                } catch (IllegalArgumentException e) {
                    e.printStackTrace();
                }
                // datePicker.getCalendarView().setVisibility(View.GONE);
                ((View) dayPicker).setVisibility(View.GONE);
            }
        }
    }

    public void onClick(DialogInterface dialog, int which) {
        // Log.d(this.getClass().getSimpleName(), String.format("which:%d",
        // which));
        // 如果是“取 消”按钮，则返回，如果是“确 定”按钮，则往下执行
        if (which == BUTTON_POSITIVE)
            tryNotifyDateSet();
    }

    @Override
    public void onDateChanged(DatePicker view, int year, int month, int day) {
        if (view.getId() == R.id.datePickerStart)
            mDatePicker_start.init(year, month, day, this);
        if (view.getId() == R.id.datePickerEnd)
            mDatePicker_end.init(year, month, day, this);
        // updateTitle(year, month, day);
    }

    /**
     * 获得开始日期的DatePicker
     *
     * @return The calendar view.
     */
    public DatePicker getDatePickerStart() {
        return mDatePicker_start;
    }

    /**
     * 获得结束日期的DatePicker
     *
     * @return The calendar view.
     */
    public DatePicker getDatePickerEnd() {
        return mDatePicker_end;
    }

    /**
     * Sets the start date.
     *
     * @param year
     *            The date year.
     * @param monthOfYear
     *            The date month.
     * @param dayOfMonth
     *            The date day of month.
     */
    public void updateStartDate(int year, int monthOfYear, int dayOfMonth) {
        mDatePicker_start.updateDate(year, monthOfYear, dayOfMonth);
    }

    /**
     * Sets the end date.
     *
     * @param year
     *            The date year.
     * @param monthOfYear
     *            The date month.
     * @param dayOfMonth
     *            The date day of month.
     */
    public void updateEndDate(int year, int monthOfYear, int dayOfMonth) {
        mDatePicker_end.updateDate(year, monthOfYear, dayOfMonth);
    }

    private void tryNotifyDateSet() {
        if (mCallBack != null) {
            mDatePicker_start.clearFocus();
            mDatePicker_end.clearFocus();
            mCallBack.onDateSet(mDatePicker_start, mDatePicker_start.getYear(), mDatePicker_start.getMonth(),
                    mDatePicker_start.getDayOfMonth(), mDatePicker_end, mDatePicker_end.getYear(),
                    mDatePicker_end.getMonth(), mDatePicker_end.getDayOfMonth());
        }
    }

    @Override
    protected void onStop() {
        // tryNotifyDateSet();
        super.onStop();
    }

    @Override
    public Bundle onSaveInstanceState() {
        Bundle state = super.onSaveInstanceState();
        state.putInt(START_YEAR, mDatePicker_start.getYear());
        state.putInt(START_MONTH, mDatePicker_start.getMonth());
        state.putInt(START_DAY, mDatePicker_start.getDayOfMonth());
        state.putInt(END_YEAR, mDatePicker_end.getYear());
        state.putInt(END_MONTH, mDatePicker_end.getMonth());
        state.putInt(END_DAY, mDatePicker_end.getDayOfMonth());
        return state;
    }

    @Override
    public void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        int start_year = savedInstanceState.getInt(START_YEAR);
        int start_month = savedInstanceState.getInt(START_MONTH);
        int start_day = savedInstanceState.getInt(START_DAY);
        mDatePicker_start.init(start_year, start_month, start_day, this);

        int end_year = savedInstanceState.getInt(END_YEAR);
        int end_month = savedInstanceState.getInt(END_MONTH);
        int end_day = savedInstanceState.getInt(END_DAY);
        mDatePicker_end.init(end_year, end_month, end_day, this);

    }
}

这些代码是以DatePickerDialog.java为基础修改的。总的来说，阅读源码是一种好习惯。这里面最需要注意的是hidDay方法，该方法如果调用，则隐藏“日”的选择框，只能选择“年月”。这个方法的实现也比较有难度，需要通过反射，找出DatePicker中表示日的字段，并将其设置为隐藏。

还有一点需要注意的是，为了让控件显示更加好看，我用了一张名字为fenge.png的图片，图片在我提供的源码中可以找到。

下面就需要编辑activity_main.xml了，这个内容相当简单，只要一个显示的text和一个button即可，代码如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/LinearLayout01"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <EditText
        android:id="@+id/et"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:cursorVisible="false"
        android:editable="false" />

    <Button
        android:id="@+id/dateBtn"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="日期对话框" />

</LinearLayout>

最后，在MainActivity.java中，加入测试代码：

package com.example.doubledatepicker;

import java.util.Calendar;

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

public class MainActivity extends Activity {

    Button btn;
    TextView et;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        btn = (Button) findViewById(R.id.dateBtn);
        et = (TextView) findViewById(R.id.et);

        btn.setOnClickListener(new View.OnClickListener() {
            Calendar c = Calendar.getInstance();

            @Override
            public void onClick(View v) {
                // 最后一个false表示不显示日期，如果要显示日期，最后参数可以是true或者不用输入
                new DoubleDatePickerDialog(MainActivity.this, 0, new DoubleDatePickerDialog.OnDateSetListener() {

                    @Override
                    public void onDateSet(DatePicker startDatePicker, int startYear, int startMonthOfYear,
                            int startDayOfMonth, DatePicker endDatePicker, int endYear, int endMonthOfYear,
                            int endDayOfMonth) {
                        String textString = String.format("开始时间：%d-%d-%d
结束时间：%d-%d-%d
", startYear,
                                startMonthOfYear + 1, startDayOfMonth, endYear, endMonthOfYear + 1, endDayOfMonth);
                        et.setText(textString);
                    }
                }, c.get(Calendar.YEAR), c.get(Calendar.MONTH), c.get(Calendar.DATE), true).show();
            }
        });
    }
}

可以看到，在新建DoubleDatePickerDialog时， 我们实现了一个new DoubleDatePickerDialog.OnDateSetListener()的匿名类，这个类被DoubleDatePickerDialog引用，当DoubleDatePickerDialog中的“确 定”按钮被点击时，就会调用匿名类的onDateSet方法。（这也是事件绑定的基本原理）。

DoubleDatePickerDialog构造函数的最后一个参数，true为显示日期，false为不显示日期。

当最后一个参数为true时，显示效果如下：

当最后一个参数为false时，显示如下

源码下载地址：https://github.com/jilianggqq/DoubleDatePicker