Android View横向滑动（Android Guide Activity） ViewPager

我们可以发现现在很多Android App都可以通过手势横向滑动页面，是怎么实现的呢？

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

1	<?xmlversion="1.0"encoding="utf-8"?>

2	<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"

3	android:layout_width="fill_parent"

4	android:layout_height="fill_parent"android:orientation="vertical">

5	<!-- 此处需要给出全路径 -->

6	<android.support.v4.view.ViewPager

7	android:id="@+id/viewpagerLayout"android:layout_height="fill_parent"android:layout_width="fill_parent"/>

8	</LinearLayout>

layout1.xml

1	<?xmlversion="1.0"encoding="utf-8"?>

2	<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"

3	android:layout_width="fill_parent"

4	android:layout_height="fill_parent"android:orientation="vertical">

5	<TextViewandroid:textAppearance="?android:attr/textAppearanceLarge"android:layout_height="wrap_content"android:id="@+id/textView1"android:layout_width="fill_parent"android:text="第一页"></TextView>

6	<EditTextandroid:layout_width="match_parent"android:layout_height="wrap_content"android:id="@+id/editText1">

7	<requestFocus></requestFocus>

8	</EditText>

9	</LinearLayout>

layout2.xml

1	<?xmlversion="1.0"encoding="utf-8"?>

2	<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"

3	android:layout_width="fill_parent"

4	android:layout_height="fill_parent"android:orientation="vertical">

5	<TextViewandroid:textAppearance="?android:attr/textAppearanceLarge"android:layout_height="wrap_content"android:id="@+id/textView1"android:layout_width="fill_parent"android:text="第二页"></TextView>

6	<EditTextandroid:layout_width="match_parent"android:layout_height="wrap_content"android:id="@+id/editText1">

7	<requestFocus></requestFocus>

8	</EditText>

9	</LinearLayout>

layout3.xml

1	<?xmlversion="1.0"encoding="utf-8"?>

2	<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"

3	android:layout_width="fill_parent"

4	android:layout_height="fill_parent"android:orientation="vertical">

5	<TextViewandroid:textAppearance="?android:attr/textAppearanceLarge"android:layout_height="wrap_content"android:id="@+id/textView1"android:layout_width="fill_parent"android:text="第三页"></TextView>

6	<EditTextandroid:layout_width="match_parent"android:layout_height="wrap_content"android:id="@+id/editText1">

7	<requestFocus></requestFocus>

8	</EditText>

9	</LinearLayout>

主程序

001	packagea.b;

002

003	importjava.util.ArrayList;

004	importjava.util.List;

005

006	importandroid.app.Activity;

007	importandroid.os.Bundle;

008	importandroid.os.Parcelable;

009	importandroid.support.v4.view.PagerAdapter;

010	importandroid.support.v4.view.ViewPager;

011	importandroid.support.v4.view.ViewPager.OnPageChangeListener;

012	importandroid.util.Log;

013	importandroid.view.LayoutInflater;

014	importandroid.view.View;

015	importandroid.widget.EditText;

016

017	publicclassTestViewPagerextendsActivity {

018	privateViewPager myViewPager;

019

020	privateMyPagerAdapter myAdapter;

021

022	privateLayoutInflater mInflater;

023	privateList<View> mListViews;

024	privateView layout1 =null;

025	privateView layout2 =null;

026	privateView layout3 =null;

027

028

@Override

029	protectedvoidonCreate(Bundle savedInstanceState) {

030	super.onCreate(savedInstanceState);

031	setContentView(R.layout.viewpager_layout);

032	myAdapter =newMyPagerAdapter();

033	myViewPager = (ViewPager) findViewById(R.id.viewpagerLayout);

034	myViewPager.setAdapter(myAdapter);

035

036	mListViews =newArrayList<View>();

037	mInflater = getLayoutInflater();

038	layout1 = mInflater.inflate(R.layout.layout1,null);

039	layout2 = mInflater.inflate(R.layout.layout2,null);

040	layout3 = mInflater.inflate(R.layout.layout3,null);

041

042	mListViews.add(layout1);

043	mListViews.add(layout2);

044	mListViews.add(layout3);

045

046	//初始化当前显示的view

047	myViewPager.setCurrentItem(1);

048

049	//初始化第二个view的信息

050	EditText v2EditText = (EditText)layout2.findViewById(R.id.editText1);

051	v2EditText.setText("动态设置第二个view的值");

052

053	myViewPager.setOnPageChangeListener(newOnPageChangeListener() {

054

055

@Override

056	publicvoidonPageSelected(intarg0) {

057	Log.d("k","onPageSelected - "+ arg0);

058	//activity从1到2滑动，2被加载后掉用此方法

059	View v = mListViews.get(arg0);

060	EditText editText = (EditText)v.findViewById(R.id.editText1);

061	editText.setText("动态设置#"+arg0+"edittext控件的值");

062

}

063

064

@Override

065	publicvoidonPageScrolled(intarg0,floatarg1,intarg2) {

066	Log.d("k","onPageScrolled - "+ arg0);

067	//从1到2滑动，在1滑动前调用

068

}

069

070

@Override

071	publicvoidonPageScrollStateChanged(intarg0) {

072	Log.d("k","onPageScrollStateChanged - "+ arg0);

073	//状态有三个0空闲，1是增在滑行中，2目标加载完毕

074

/**

075	* Indicates that the pager is in an idle, settled state. The current page

076	* is fully in view and no animation is in progress.

077

*/

078	//public static final int SCROLL_STATE_IDLE = 0;

079

/**

080	* Indicates that the pager is currently being dragged by the user.

081

*/

082	//public static final int SCROLL_STATE_DRAGGING = 1;

083

/**

084	* Indicates that the pager is in the process of settling to a final position.

085

*/

086	//public static final int SCROLL_STATE_SETTLING = 2;

087

088

}

089

});

090

091

}

092

093	privateclassMyPagerAdapterextendsPagerAdapter{

094

095

@Override

096	publicvoiddestroyItem(View arg0,intarg1, Object arg2) {

097	Log.d("k","destroyItem");

098	((ViewPager) arg0).removeView(mListViews.get(arg1));

099

}

100

101

@Override

102	publicvoidfinishUpdate(View arg0) {

103	Log.d("k","finishUpdate");

104

}

105

106

@Override

107	publicintgetCount() {

108	Log.d("k","getCount");

109	returnmListViews.size();

110

}

111

112

@Override

113	publicObject instantiateItem(View arg0,intarg1) {

114	Log.d("k","instantiateItem");

115	((ViewPager) arg0).addView(mListViews.get(arg1),0);

116	returnmListViews.get(arg1);

117

}

118

119

@Override

120	publicbooleanisViewFromObject(View arg0, Object arg1) {

121	Log.d("k","isViewFromObject");

122	returnarg0==(arg1);

123

}

124

125

@Override

126	publicvoidrestoreState(Parcelable arg0, ClassLoader arg1) {

127	Log.d("k","restoreState");

128

}

129

130

@Override

131	publicParcelable saveState() {

132	Log.d("k","saveState");

133	returnnull;

134

}

135

136

@Override

137	publicvoidstartUpdate(View arg0) {

138	Log.d("k","startUpdate");

139

}

140

141

}

142

143

}

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

*/

也可以参照：
http://www.cnblogs.com/dwinter/archive/2012/02/27/2369590.html