android中的左右滑屏实现By ViewPager

先看效果，就是左右滑屏的效果

具体实现详解

android compatibility package, revision 3在7月份发布后，其中有个ViewPager引起了我的注意

官方的描述：

 请参考：http://developer.android.com/sdk/compatibility-library.html#Notes

ViewPager的下载与安装

首先通过SDK Manager更新最新版android compatibility package, revision 3

更新后，在eclipse中工程上点击右键，选择android tools -> add compatibility library即可完成安装

实际上就是一个jar包，手工导到工程中也可

jar包所在位置是\android-sdk\extras\android\compatibility\v4\android-support-v4.jar

至此准备环境已经ok

下边还是通过代码进行说话吧

准备布局文件

viewpager_layout.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent" android:orientation="vertical"><!-- 此处需要给出全路径 --><android.support.v4.view.ViewPager    android:id="@+id/viewpagerLayout" android:layout_height="fill_parent" android:layout_width="fill_parent"/></LinearLayout>

layout1.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent" android:orientation="vertical">    <TextView android:textAppearance="?android:attr/textAppearanceLarge" android:layout_height="wrap_content" android:id="@+id/textView1" android:layout_width="fill_parent" android:text="第一页"></TextView>    <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/editText1">        <requestFocus></requestFocus>    </EditText></LinearLayout>

layout2.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent" android:orientation="vertical">    <TextView android:textAppearance="?android:attr/textAppearanceLarge" android:layout_height="wrap_content" android:id="@+id/textView1" android:layout_width="fill_parent" android:text="第二页"></TextView>    <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/editText1">        <requestFocus></requestFocus>    </EditText></LinearLayout>

layout3.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent" android:orientation="vertical">    <TextView android:textAppearance="?android:attr/textAppearanceLarge" android:layout_height="wrap_content" android:id="@+id/textView1" android:layout_width="fill_parent" android:text="第三页"></TextView>    <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/editText1">        <requestFocus></requestFocus>    </EditText></LinearLayout>

主程序

package a.b;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.os.Bundle;import android.os.Parcelable;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.support.v4.view.ViewPager.OnPageChangeListener;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.widget.EditText;public class TestViewPager extends Activity {private ViewPager myViewPager;private MyPagerAdapter myAdapter;private LayoutInflater mInflater;private List<View> mListViews;private View layout1 = null;private View layout2 = null;private View layout3 = null;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.viewpager_layout);myAdapter = new MyPagerAdapter();myViewPager = (ViewPager) findViewById(R.id.viewpagerLayout);myViewPager.setAdapter(myAdapter);                mListViews = new ArrayList<View>();        mInflater = getLayoutInflater();        layout1 = mInflater.inflate(R.layout.layout1, null);        layout2 = mInflater.inflate(R.layout.layout2, null);        layout3 = mInflater.inflate(R.layout.layout3, null);               mListViews.add(layout1);        mListViews.add(layout2);        mListViews.add(layout3);                //初始化当前显示的view        myViewPager.setCurrentItem(1);                //初始化第二个view的信息        EditText v2EditText = (EditText)layout2.findViewById(R.id.editText1);        v2EditText.setText("动态设置第二个view的值");                myViewPager.setOnPageChangeListener(new OnPageChangeListener() {@Overridepublic void onPageSelected(int arg0) {Log.d("k", "onPageSelected - " + arg0);//activity从1到2滑动，2被加载后掉用此方法View v = mListViews.get(arg0);EditText editText = (EditText)v.findViewById(R.id.editText1);editText.setText("动态设置#"+arg0+"edittext控件的值");}@Overridepublic void onPageScrolled(int arg0, float arg1, int arg2) {Log.d("k", "onPageScrolled - " + arg0);//从1到2滑动，在1滑动前调用}@Overridepublic void onPageScrollStateChanged(int arg0) {Log.d("k", "onPageScrollStateChanged - " + arg0);//状态有三个0空闲，1是增在滑行中，2目标加载完毕/**     * Indicates that the pager is in an idle, settled state. The current page     * is fully in view and no animation is in progress.     */    //public static final int SCROLL_STATE_IDLE = 0;    /**     * Indicates that the pager is currently being dragged by the user.     */    //public static final int SCROLL_STATE_DRAGGING = 1;    /**     * Indicates that the pager is in the process of settling to a final position.     */    //public static final int SCROLL_STATE_SETTLING = 2;}});        }    private class MyPagerAdapter extends PagerAdapter{@Overridepublic void destroyItem(View arg0, int arg1, Object arg2) {Log.d("k", "destroyItem");((ViewPager) arg0).removeView(mListViews.get(arg1));}@Overridepublic void finishUpdate(View arg0) {Log.d("k", "finishUpdate");}@Overridepublic int getCount() {Log.d("k", "getCount");return mListViews.size();}@Overridepublic Object instantiateItem(View arg0, int arg1) {Log.d("k", "instantiateItem");((ViewPager) arg0).addView(mListViews.get(arg1),0);return mListViews.get(arg1);}@Overridepublic boolean isViewFromObject(View arg0, Object arg1) {Log.d("k", "isViewFromObject");return arg0==(arg1);}@Overridepublic void restoreState(Parcelable arg0, ClassLoader arg1) {Log.d("k", "restoreState");}@Overridepublic Parcelable saveState() {Log.d("k", "saveState");return null;}@Overridepublic void startUpdate(View arg0) {Log.d("k", "startUpdate");}        }}

在实机上测试后，非常流畅，这也就是说官方版的左右滑屏控件已经实现

目前，关于viewpager的文章非常少，本文是通过阅读viewpager源代码分析出的写法

当然此文章仅是抛砖引玉，而且属于框架式程序，目的就是让读者了解API的基本用法

希望这篇原创文章对大家有帮助

欢迎感兴趣的朋友一起讨论

共同学习，共同进步

另外，ViewPager的注释上有这么一段话，大体意思是该控件目前属于早期实现，后续会有修改

01/**

02 * Layout manager that allows the user to flip left and right

03 * through pages of data.  You supply an implementation of a

04 * {@link PagerAdapter} to generate the pages that the view shows.

05 *

06 * <p>Note this class is currently under early design and

07 * development.  The API will likely change in later updates of

08 * the compatibility library, requiring changes to the source code

09 * of apps when they are compiled against the newer version.</p>

10 */