android图片轮播

第一步，先写布局文件

[html] view
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<com.main.util.SlideShowView

android:id="@+id/slideshowView"

android:layout_width="fill_parent"

android:layout_height="300dp"

android:layout_centerHorizontal="true"

/>

第二步，java代码

[java] view
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package com.main.util;



import java.util.ArrayList;

import java.util.List;

import java.util.concurrent.Executors;

import java.util.concurrent.ScheduledExecutorService;

import java.util.concurrent.TimeUnit;



import com.main.R;



import android.content.Context;

import android.graphics.drawable.Drawable;

import android.os.Handler;

import android.os.Message;

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.AttributeSet;

import android.view.LayoutInflater;

import android.view.View;

import android.widget.FrameLayout;

import android.widget.ImageView;

import android.widget.ImageView.ScaleType;





public class SlideShowView extends FrameLayout {

//轮播图图片数量

private final static int IMAGE_COUNT = 5;

//自动轮播的时间间隔

private final static int TIME_INTERVAL = 5;

//自动轮播启用开关

private final static boolean isAutoPlay = true;



//自定义轮播图的资源ID

private int[] imagesResIds;

//放轮播图片的ImageView 的list

private List<ImageView> imageViewsList;

//放圆点的View的list

private List<View> dotViewsList;



private ViewPager viewPager;

//当前轮播页

private int currentItem = 0;

//定时任务

private ScheduledExecutorService scheduledExecutorService;

//Handler

private Handler handler = new Handler(){



@Override

public void handleMessage(Message msg) {

// TODO Auto-generated method stub

super.handleMessage(msg);

viewPager.setCurrentItem(currentItem);

}



};



public SlideShowView(Context context) {

this(context,null);

// TODO Auto-generated constructor stub

}

public SlideShowView(Context context, AttributeSet attrs) {

this(context, attrs, 0);

// TODO Auto-generated constructor stub

}

public SlideShowView(Context context, AttributeSet attrs, int defStyle) {

super(context, attrs, defStyle);

// TODO Auto-generated constructor stub

initData();

initUI(context);

if(isAutoPlay){

startPlay();

}



}

/**

* 开始轮播图切换

*/

private void startPlay(){

scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();

scheduledExecutorService.scheduleAtFixedRate(new SlideShowTask(), 1, 4, TimeUnit.SECONDS);

}

/**

* 停止轮播图切换

*/

private void stopPlay(){

scheduledExecutorService.shutdown();

}

/**

* 初始化相关Data

*/

private void initData(){

imagesResIds = new int[]{//图片数据

R.drawable.p1,

R.drawable.p2,

};

imageViewsList = new ArrayList<ImageView>();

dotViewsList = new ArrayList<View>();



}

/**

* 初始化Views等UI

*/

private void initUI(Context context){

LayoutInflater.from(context).inflate(R.layout.imageviewpager, this, true);

for(int imageID : imagesResIds){

ImageView view = new ImageView(context);

view.setImageResource(imageID);

view.setScaleType(ScaleType.FIT_XY);

imageViewsList.add(view);

}

dotViewsList.add(findViewById(R.id.v_dot1));

dotViewsList.add(findViewById(R.id.v_dot2));



viewPager = (ViewPager) findViewById(R.id.viewPager);

viewPager.setFocusable(true);



viewPager.setAdapter(new MyPagerAdapter());

viewPager.setOnPageChangeListener(new MyPageChangeListener());

}



/**

* 填充ViewPager的页面适配器

* @author caizhiming

*/

private class MyPagerAdapter extends PagerAdapter{



@Override

public void destroyItem(View container, int position, Object object) {

// TODO Auto-generated method stub

//((ViewPag.er)container).removeView((View)object);

((ViewPager)container).removeView(imageViewsList.get(position));

}



@Override

public Object instantiateItem(View container, int position) {

// TODO Auto-generated method stub

((ViewPager)container).addView(imageViewsList.get(position));

return imageViewsList.get(position);

}



@Override

public int getCount() {

// TODO Auto-generated method stub

return imageViewsList.size();

}



@Override

public boolean isViewFromObject(View arg0, Object arg1) {

// TODO Auto-generated method stub

return arg0 == arg1;

}

@Override

public void restoreState(Parcelable arg0, ClassLoader arg1) {

// TODO Auto-generated method stub



}



@Override

public Parcelable saveState() {

// TODO Auto-generated method stub

return null;

}



@Override

public void startUpdate(View arg0) {

// TODO Auto-generated method stub



}



@Override

public void finishUpdate(View arg0) {

// TODO Auto-generated method stub



}



}

/**

* ViewPager的监听器

* 当ViewPager中页面的状态发生改变时调用

* @author caizhiming

*/

private class MyPageChangeListener implements OnPageChangeListener{



boolean isAutoPlay = false;



@Override

public void onPageScrollStateChanged(int arg0) {

// TODO Auto-generated method stub

switch (arg0) {

case 1:// 手势滑动，空闲中

isAutoPlay = false;

break;

case 2:// 界面切换中

isAutoPlay = true;

break;

case 0:// 滑动结束，即切换完毕或者加载完毕

// 当前为最后一张，此时从右向左滑，则切换到第一张

if (viewPager.getCurrentItem() == viewPager.getAdapter().getCount() - 1 && !isAutoPlay) {

viewPager.setCurrentItem(0);

}

// 当前为第一张，此时从左向右滑，则切换到最后一张

else if (viewPager.getCurrentItem() == 0 && !isAutoPlay) {

viewPager.setCurrentItem(viewPager.getAdapter().getCount() - 1);

}

break;

}

}



@Override

public void onPageScrolled(int arg0, float arg1, int arg2) {

// TODO Auto-generated method stub



}



@Override

public void onPageSelected(int pos) {

// TODO Auto-generated method stub



currentItem = pos;

for(int i=0;i < dotViewsList.size();i++){

if(i == pos){

((View)dotViewsList.get(pos)).setBackgroundResource(R.drawable.dot_black);

}else {

((View)dotViewsList.get(i)).setBackgroundResource(R.drawable.dot_white);

}

}

}



}



/**

*执行轮播图切换任务

*@author caizhiming

*/

private class SlideShowTask implements Runnable{



@Override

public void run() {

// TODO Auto-generated method stub

synchronized (viewPager) {

currentItem = (currentItem+1)%imageViewsList.size();

handler.obtainMessage().sendToTarget();

}

}



}

/**

* 销毁ImageView资源，回收内存

* @author caizhiming

*/

private void destoryBitmaps() {



for (int i = 0; i < IMAGE_COUNT; i++) {

ImageView imageView = imageViewsList.get(i);

Drawable drawable = imageView.getDrawable();

if (drawable != null) {

//解除drawable对view的引用

drawable.setCallback(null);

}

}

}



}