安卓開發中的雙日期選擇控件（可隱藏日，只顯示年月）

在安卓開發中，會碰到選開始日期和結束日期的問題。特別是在使用Pad時，如果彈出一個Dialog，能夠同時選擇開始日期和結束日期，那將是極好的。我在開發中在DatePickerDialog的基礎上做了修改，實現了這種Dialog。效果如下：

具體實現方法為：

先新建一個安卓項目DoubleDatePicker，在res/layout文件夾下新建date_picker_dialog.xml，內容如下：

<?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="開始日期" />

        <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="結束日期" />

        <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 默認包下新建文件DoubleDatePickerDialog.java，內容如下：

/*
 * 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, "確 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);

        // 如果要隱藏當前日期，則使用下面方法。
        if (!isDayVisible) {
            hidDay(mDatePicker_start);
            hidDay(mDatePicker_end);
        }
    }

    /**
     * 隱藏DatePicker中的日期顯示
     * 
     * @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”按鈕，則返回，如果是“確 定”按鈕，則往下執行
        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);
    }

    /**
     * 獲得開始日期的DatePicker
     *
     * @return The calendar view.
     */
    public DatePicker getDatePickerStart() {
        return mDatePicker_start;
    }

    /**
     * 獲得結束日期的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);

    }
}

這些代碼是以DatePickerDialog.java為基礎修改的。總的來說，閱讀源碼是一種好習慣。這里面最需要注意的是hidDay方法，該方法如果調用，則隱藏“日”的選擇框，只能選擇“年月”。這個方法的實現也比較有難度，需要通過反射，找出DatePicker中表示日的字段，並將其設置為隱藏。

還有一點需要注意的是，為了讓控件顯示更加好看，我用了一張名字為fenge.png的圖片，圖片在我提供的源碼中可以找到。

下面就需要編輯activity_main.xml了，這個內容相當簡單，只要一個顯示的text和一個button即可，代碼如下：

<?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="日期對話框" />

</LinearLayout>

最后，在MainActivity.java中，加入測試代碼：

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) {
                // 最后一個false表示不顯示日期，如果要顯示日期，最后參數可以是true或者不用輸入
                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("開始時間：%d-%d-%d\n結束時間：%d-%d-%d\n", 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時， 我們實現了一個new DoubleDatePickerDialog.OnDateSetListener()的匿名類，這個類被DoubleDatePickerDialog引用，當DoubleDatePickerDialog中的“確 定”按鈕被點擊時，就會調用匿名類的onDateSet方法。（這也是事件綁定的基本原理）。

DoubleDatePickerDialog構造函數的最后一個參數，true為顯示日期，false為不顯示日期。

當最后一個參數為true時，顯示效果如下：

當最后一個參數為false時，顯示如下

 

源碼下載地址：https://github.com/jilianggqq/DoubleDatePicker