Android实现图片轮播效果

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 tools:context=".MainActivity" >

 <!-- 广告条的使用 -->

 <com.xuliugen.viewpager.MyViewPagerTransformerAnim
 android:id="@+id/viewpager"
 android:layout_width="match_parent"
 android:layout_height="200dp" />

 <!-- 广告条下边的文字 -->

 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:layout_alignBottom="@id/viewpager"
 android:background="#33000000"
 android:orientation="vertical" >

 <TextView
 android:id="@+id/image_desc"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:gravity="center"
 android:text="@string/app_name"
 android:textColor="@android:color/white"
 android:textSize="16sp" />

 <LinearLayout
 android:id="@+id/point_group"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_gravity="center_horizontal"
 android:layout_marginBottom="5dp"
 android:orientation="horizontal" >
 </LinearLayout>
 </LinearLayout>

</RelativeLayout>

package com.xuliugen.viewpager;

import java.util.HashMap;
import java.util.Map;

import android.content.Context;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.View;

import com.nineoldandroids.view.ViewHelper;

/*
 * 自定义viewpager实现动画切换效果：
 * 
 * 1、需要拿到当前切换的两个view
 * 
 * 2、一个动画的梯度值
 */
public class MyViewPagerTransformerAnim extends ViewPager {

 private View mLeft;
 private View mRight;

 private float mTrans;
 private float mScale;

 private static final float MIN_SCALE = 0.6f;
 private Map<Integer, View> mChildren = new HashMap<Integer, View>();

 /*
 * 要有两个构造方法
 */
 public MyViewPagerTransformerAnim(Context context, AttributeSet attrs) {
 super(context, attrs);
 }

 public MyViewPagerTransformerAnim(Context context) {
 super(context);
 }

 /*
 * 设置put的方法
 */
 public void setViewForPosition(View view, int position) {
 mChildren.put(position, view);
 }

 /*
 * remove的方法
 */
 public void removeViewFromPosition(Integer position) {
 mChildren.remove(position);
 }

 /**
 * 重写的方法
 */
 @Override
 protected void onPageScrolled(int position, float offset, int offsetPixels) {

 // Log.e("TAG", "position =" + position + ",offset = " + offset);
 mLeft = mChildren.get(position);
 mRight = mChildren.get(position + 1);

 animStack(mLeft, mRight, offset, offsetPixels);// 创建动画效果

 super.onPageScrolled(position, offset, offsetPixels);
 }

 private void animStack(View left, View right, float offset, int offsetPixels) {
 if (right != null) {

 // 从0-1页，offset:0`1
 mScale = (1 - MIN_SCALE) * offset + MIN_SCALE;

 mTrans = -getWidth() - getPageMargin() + offsetPixels;

 ViewHelper.setScaleX(right, mScale);
 ViewHelper.setScaleY(right, mScale);

 ViewHelper.setTranslationX(right, mTrans);
 }
 if (left != null) {
 left.bringToFront();
 }
 }
}

package com.xuliugen.viewpager;

import java.util.ArrayList;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MainActivity extends Activity {

 private ViewPager viewPager;

 private LinearLayout pointGroup;

 private TextView iamgeDesc;

 // 图片资源ID
 private final int[] imageIds = { R.drawable.a, R.drawable.b, R.drawable.c,
 R.drawable.d, R.drawable.e };

 // 图片标题集合
 private final String[] imageDescriptions = { "巩俐不低俗，我就不能低俗",
 "扑树又回来啦！再唱经典老歌引万人大合唱", "揭秘北京电影如何升级", "乐视网TV版大派送", "热血?潘康姆瓷?" };

 private ArrayList<ImageView> imageList;

 /**
 * 上一个页面的位置
 */
 protected int lastPosition;

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

 viewPager = (ViewPager) findViewById(R.id.viewpager);
 pointGroup = (LinearLayout) findViewById(R.id.point_group);
 iamgeDesc = (TextView) findViewById(R.id.image_desc);
 iamgeDesc.setText(imageDescriptions[0]);

 imageList = new ArrayList<ImageView>();
 for (int i = 0; i < imageIds.length; i++) {

 // 初始化图片资源
 ImageView image = new ImageView(this);
 image.setBackgroundResource(imageIds[i]);
 imageList.add(image);

 // 添加指示点
 ImageView point = new ImageView(this);
 LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
  LinearLayout.LayoutParams.WRAP_CONTENT,
  LinearLayout.LayoutParams.WRAP_CONTENT);

 params.rightMargin = 20;
 point.setLayoutParams(params);

 point.setBackgroundResource(R.drawable.point_bg);
 if (i == 0) {
 point.setEnabled(true);
 } else {
 point.setEnabled(false);
 }
 pointGroup.addView(point);
 }

 viewPager.setAdapter(new MyPagerAdapter());

 // viewPager.setCurrentItem(Integer.MAX_VALUE/2 -
 // (Integer.MAX_VALUE/2%imageList.size())) ;

 viewPager.setOnPageChangeListener(new OnPageChangeListener() {

 @Override
 /**
 * 页面切换后调用 
 * position 新的页面位置
 */
 public void onPageSelected(int position) {

 position = position % imageList.size();

 // 设置文字描述内容
 iamgeDesc.setText(imageDescriptions[position]);

 // 改变指示点的状态
 // 把当前点enbale 为true
 pointGroup.getChildAt(position).setEnabled(true);
 // 把上一个点设为false
 pointGroup.getChildAt(lastPosition).setEnabled(false);
 lastPosition = position;

 }

 @Override
 /**
 * 页面正在滑动的时候，回调
 */
 public void onPageScrolled(int position, float positionOffset,
  int positionOffsetPixels) {
 }

 @Override
 /**
 * 当页面状态发生变化的时候，回调
 */
 public void onPageScrollStateChanged(int state) {

 }
 });

 /*
 * 自动循环： 1、定时器：Timer 2、开子线程 while true 循环 3、ColckManager 4、 用handler
 * 发送延时信息，实现循环
 */
 isRunning = true;
 // 设置图片的自动滑动
 handler.sendEmptyMessageDelayed(0, 3000);
 }

 /**
 * 判断是否自动滚动
 */
 private boolean isRunning = false;

 private Handler handler = new Handler() {
 public void handleMessage(android.os.Message msg) {

 // 让viewPager 滑动到下一页
 viewPager.setCurrentItem(viewPager.getCurrentItem() + 1);
 if (isRunning) {
 handler.sendEmptyMessageDelayed(0, 3000);
 }
 };
 };

 protected void onDestroy() {

 isRunning = false;
 };

 private class MyPagerAdapter extends PagerAdapter {

 @Override
 /**
 * 获得页面的总数
 */
 public int getCount() {
 return Integer.MAX_VALUE; // 使得图片可以循环
 }

 @Override
 /**
 * 获得相应位置上的view
 * container view的容器，其实就是viewpager自身
 * position 相应的位置
 */
 public Object instantiateItem(ViewGroup container, int position) {

 // System.out.println("instantiateItem ::" + position);

 // 给 container 添加一个view
 container.addView(imageList.get(position % imageList.size()));
 // 返回一个和该view相对的object
 return imageList.get(position % imageList.size());
 }

 @Override
 /**
 * 判断 view和object的对应关系 
 */
 public boolean isViewFromObject(View view, Object object) {
 if (view == object) {
 return true;
 } else {
 return false;
 }
 }

 @Override
 /**
 * 销毁对应位置上的object
 */
 public void destroyItem(ViewGroup container, int position, Object object) {
 // System.out.println("destroyItem ::" + position);

 container.removeView((View) object);
 object = null;
 }
 }

}

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

 <item android:drawable="@drawable/point_nomal" android:state_enabled="false"/>
 <item android:drawable="@drawable/point_focured" android:state_enabled="true"/>

</selector>