一、首先,我们来看一下效果图,这是新浪微博的Tab滑动效果。我们可以手势滑动,也可以点击上面的头标进行切换。与此同方式,
白色横条会移动到相应的页卡头标下。这是一个动画效果,白条是缓慢滑动过去的。好了,接下来我们就来实现它。
二、在开始前,我们先要认识一个控件,ViewPager。它是是google SDk中自带的一个附加包的一个类,可以用来实现屏幕间的切换。
这个附加包是android-support-v4.jar,在最后的源码中会提供给大家,在libs文件夹中。当然你也可以自己从网上搜索最新的版本。
找到它后,我们需要在项目中添加
三、我们先做界面,
界面设计很简单,第一行三个头标,第二行动画图片,第三行页卡内容展示。
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<? xml version = "1.0" encoding = "utf-8" ?>
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< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
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xmlns:umadsdk = "http://schemas.android.com/apk/res/com.LoveBus"
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android:layout_width = "fill_parent"
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android:layout_height = "fill_parent"
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android:orientation = "vertical" >
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< LinearLayout
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android:id = "@+id/linearLayout1"
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android:layout_width = "fill_parent"
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android:layout_height = "100.0dip"
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android:background = "#FFFFFF" >
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< TextView
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android:id = "@+id/text1"
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android:layout_width = "fill_parent"
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android:layout_height = "fill_parent"
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android:layout_weight = "1.0"
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android:gravity = "center"
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android:text = "页卡1"
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android:textColor = "#000000"
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android:textSize = "22.0dip" />
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< TextView
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android:id = "@+id/text2"
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android:layout_width = "fill_parent"
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android:layout_height = "fill_parent"
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android:layout_weight = "1.0"
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android:gravity = "center"
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android:text = "页卡2"
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android:textColor = "#000000"
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android:textSize = "22.0dip" />
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< TextView
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android:id = "@+id/text3"
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android:layout_width = "fill_parent"
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android:layout_height = "fill_parent"
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android:layout_weight = "1.0"
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android:gravity = "center"
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android:text = "页卡3"
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android:textColor = "#000000"
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android:textSize = "22.0dip" />
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</ LinearLayout >
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< ImageView
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android:id = "@+id/cursor"
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android:layout_width = "fill_parent"
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android:layout_height = "wrap_content"
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android:scaleType = "matrix"
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android:src = "@drawable/a" />
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< android.support.v4.view.ViewPager
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android:id = "@+id/vPager"
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android:layout_width = "wrap_content"
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android:layout_height = "wrap_content"
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android:layout_gravity = "center"
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android:layout_weight = "1.0"
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android:background = "#000000"
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android:flipInterval = "30"
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android:persistentDrawingCache = "animation" />
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</ LinearLayout >
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我们要展示三个页卡,所以还需要三个页卡内容的界面设计,这里我们只设置了背景颜色,能起到区别作用即可。
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<? xml version = "1.0" encoding = "utf-8" ?>
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< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
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android:layout_width = "fill_parent"
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android:layout_height = "fill_parent"
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android:orientation = "vertical"
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android:background = "#158684" >
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</ LinearLayout >
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四、代码部分要进行初始化的工作
(1) 先来变量的定义
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private ViewPager
mPager; //页卡内容
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private List<View>
listViews; //
Tab页面列表
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private ImageView
cursor; //
动画图片
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private TextView
t1, t2, t3; //
页卡头标
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private int offset
= 0 ; //
动画图片偏移量
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private int currIndex
= 0 ; //
当前页卡编号
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private int bmpW; //
动画图片宽度
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/**
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*
初始化头标
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*/
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private void InitTextView()
{
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t1
= (TextView) findViewById(R.id.text1);
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t2
= (TextView) findViewById(R.id.text2);
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t3
= (TextView) findViewById(R.id.text3);
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t1.setOnClickListener( new MyOnClickListener( 0 ));
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t2.setOnClickListener( new MyOnClickListener( 1 ));
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t3.setOnClickListener( new MyOnClickListener( 2 ));
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}
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/**
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*
头标点击监听
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*/
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public class MyOnClickListener implements View.OnClickListener
{
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private int index
= 0 ;
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public MyOnClickListener( int i)
{
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index
= i;
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}
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@Override
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public void onClick(View
v) {
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mPager.setCurrentItem(index);
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}
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};
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相信大家看后都没什么问题,点击第几个,就展示第几个页卡内容。
(3) 初始化页卡内容区
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/**
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*
初始化ViewPager
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*/
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private void InitViewPager()
{
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mPager
= (ViewPager) findViewById(R.id.vPager);
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listViews
= new ArrayList<View>();
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LayoutInflater
mInflater = getLayoutInflater();
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listViews.add(mInflater.inflate(R.layout.lay1, null ));
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listViews.add(mInflater.inflate(R.layout.lay2, null ));
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listViews.add(mInflater.inflate(R.layout.lay3, null ));
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mPager.setAdapter( new MyPagerAdapter(listViews));
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mPager.setCurrentItem( 0 );
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mPager.setOnPageChangeListener( new MyOnPageChangeListener());
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}
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我们将三个页卡界面装入其中,默认显示第一个页卡。这里我们还需要实现一个适配器。
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/**
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*
ViewPager适配器
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*/
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public class MyPagerAdapter extends PagerAdapter
{
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public List<View>
mListViews;
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public MyPagerAdapter(List<View>
mListViews) {
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this .mListViews
= mListViews;
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}
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@Override
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public void destroyItem(View
arg0, int arg1,
Object arg2) {
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((ViewPager)
arg0).removeView(mListViews.get(arg1));
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}
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@Override
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public void finishUpdate(View
arg0) {
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}
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@Override
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public int getCount()
{
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return mListViews.size();
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}
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@Override
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public Object
instantiateItem(View arg0, int arg1)
{
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((ViewPager)
arg0).addView(mListViews.get(arg1), 0 );
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return mListViews.get(arg1);
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}
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@Override
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public boolean isViewFromObject(View
arg0, Object arg1) {
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return arg0
== (arg1);
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}
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@Override
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public void restoreState(Parcelable
arg0, ClassLoader arg1) {
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}
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@Override
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public Parcelable
saveState() {
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return null ;
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}
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@Override
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public void startUpdate(View
arg0) {
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}
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}
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这里我们实现了各页卡的装入和卸载
(3) 初始化动画
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/**
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*
初始化动画
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*/
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private void InitImageView()
{
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cursor
= (ImageView) findViewById(R.id.cursor);
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bmpW
= BitmapFactory.decodeResource(getResources(), R.drawable.a)
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.getWidth(); //
获取图片宽度
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DisplayMetrics
dm = new DisplayMetrics();
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getWindowManager().getDefaultDisplay().getMetrics(dm);
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int screenW
= dm.widthPixels; //
获取分辨率宽度
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offset
= (screenW / 3 -
bmpW) / 2 ; //
计算偏移量
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Matrix
matrix = new Matrix();
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matrix.postTranslate(offset, 0 );
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cursor.setImageMatrix(matrix); //
设置动画初始位置
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}
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根据屏幕的分辨率和图片的宽度计算动画移动的偏移量
实现页卡切换监听
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/**
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*
页卡切换监听
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*/
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public class MyOnPageChangeListener implements OnPageChangeListener
{
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int one
= offset * 2 +
bmpW; //
页卡1 -> 页卡2 偏移量
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int two
= one * 2 ; //
页卡1 -> 页卡3 偏移量
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@Override
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public void onPageSelected( int arg0)
{
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Animation
animation = null ;
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switch (arg0)
{
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case 0 :
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if (currIndex
== 1 )
{
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animation
= new TranslateAnimation(one, 0 , 0 , 0 );
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} else if (currIndex
== 2 )
{
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animation
= new TranslateAnimation(two, 0 , 0 , 0 );
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}
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break ;
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case 1 :
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if (currIndex
== 0 )
{
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animation
= new TranslateAnimation(offset,
one, 0 , 0 );
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} else if (currIndex
== 2 )
{
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animation
= new TranslateAnimation(two,
one, 0 , 0 );
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}
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break ;
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case 2 :
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if (currIndex
== 0 )
{
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animation
= new TranslateAnimation(offset,
two, 0 , 0 );
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} else if (currIndex
== 1 )
{
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animation
= new TranslateAnimation(one,
two, 0 , 0 );
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}
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break ;
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}
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currIndex
= arg0;
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animation.setFillAfter( true ); //
True:图片停在动画结束位置
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animation.setDuration( 300 );
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cursor.startAnimation(animation);
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}
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@Override
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public void onPageScrolled( int arg0, float arg1, int arg2)
{
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}
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@Override
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public void onPageScrollStateChanged( int arg0)
{
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}
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}
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五、打完收工,快来看看自己的劳动成果吧
源码分享:http://115.com/file/dpi0unyg
转自:http://www.cnblogs.com/dwinter/archive/2012/02/27/2369590.html