[android]bunner的自动滚动和手动滑动

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本demo实现的一个图片的自动滚动和手动滑动的操作。一般的app在首先都会有一个展示的bunner条，该bunner实现了图片的自动和手动的操作的方法。喜欢的朋友可以看下,代码比较简单，注释的也比较详细。

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package com.tony.viewpager;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
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.view.View;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
import android.widget.TextView;

/**
* 仿优酷Android客户端图片左右滑动
*
*/
public class MyViewPagerActivity extends Activity {
private ViewPager viewPager; // android-support-v4中的滑动组件
private List<ImageView> imageViews; // 滑动的图片集合

private String[] titles; // 图片标题
private int[] imageResId; // 图片ID
private List<View> dots; // 图片标题正文的那些点

private TextView tv_title;
private int currentItem = 0; // 当前图片的索引号

// An ExecutorService that can schedule commands to run after a given delay,
// or to execute periodically.
private ScheduledExecutorService scheduledExecutorService;

// 切换当前显示的图片
private Handler handler = new Handler() {
public void handleMessage(android.os.Message msg) {
viewPager.setCurrentItem(currentItem);// 切换当前显示的图片
};
};

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

imageResId = new int[] { R.drawable.a, R.drawable.b, R.drawable.c, R.drawable.d, R.drawable.e };
titles = new String[imageResId.length];
titles[0] = "巩俐不低俗，我就不能低俗";
titles[1] = "扑树又回来啦！再唱经典老歌引万人大合唱";
titles[2] = "揭秘北京电影如何升级";
titles[3] = "乐视网TV版大派送";
titles[4] = "热血�丝的反杀";

imageViews = new ArrayList<ImageView>();

// 初始化图片资源
for (int i = 0; i < imageResId.length; i++) {
ImageView imageView = new ImageView(this);
imageView.setImageResource(imageResId[i]);
imageView.setScaleType(ScaleType.CENTER_CROP);
imageViews.add(imageView);
}

dots = new ArrayList<View>();
dots.add(findViewById(R.id.v_dot0));
dots.add(findViewById(R.id.v_dot1));
dots.add(findViewById(R.id.v_dot2));
dots.add(findViewById(R.id.v_dot3));
dots.add(findViewById(R.id.v_dot4));

tv_title = (TextView) findViewById(R.id.tv_title);
tv_title.setText(titles[0]);//

viewPager = (ViewPager) findViewById(R.id.vp);
viewPager.setAdapter(new MyAdapter());// 设置填充ViewPager页面的适配器
// 设置一个监听器，当ViewPager中的页面改变时调用
viewPager.setOnPageChangeListener(new MyPageChangeListener());

}

@Override
protected void onStart() {
scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();
// 当Activity显示出来后，每两秒钟切换一次图片显示
scheduledExecutorService.scheduleAtFixedRate(new ScrollTask(), 1, 2, TimeUnit.SECONDS);
super.onStart();
}

@Override
protected void onStop() {
// 当Activity不可见的时候停止切换
scheduledExecutorService.shutdown();
super.onStop();
}

/**
* 换行切换任务
*
* @author Administrator
*
*/
private class ScrollTask implements Runnable {

public void run() {
synchronized (viewPager) {
System.out.println("currentItem: " + currentItem);
currentItem = (currentItem + 1) % imageViews.size();
handler.obtainMessage().sendToTarget(); // 通过Handler切换图片
}
}

}

/**
* 当ViewPager中页面的状态发生改变时调用
*
* @author Administrator
*
*/
private class MyPageChangeListener implements OnPageChangeListener {
private int oldPosition = 0;

/**
* This method will be invoked when a new page becomes selected.
* position: Position index of the new selected page.
*/
public void onPageSelected(int position) {
currentItem = position;
tv_title.setText(titles[position]);
dots.get(oldPosition).setBackgroundResource(R.drawable.dot_normal);
dots.get(position).setBackgroundResource(R.drawable.dot_focused);
oldPosition = position;
}

public void onPageScrollStateChanged(int arg0) {

}

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

}
}

/**
* 填充ViewPager页面的适配器
*
* @author Administrator
*
*/
private class MyAdapter extends PagerAdapter {

@Override
public int getCount() {
return imageResId.length;
}

@Override
public Object instantiateItem(View arg0, int arg1) {
((ViewPager) arg0).addView(imageViews.get(arg1));
return imageViews.get(arg1);
}

@Override
public void destroyItem(View arg0, int arg1, Object arg2) {
((ViewPager) arg0).removeView((View) arg2);
}

@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}

@Override
public void restoreState(Parcelable arg0, ClassLoader arg1) {

}

@Override
public Parcelable saveState() {
return null;
}

@Override
public void startUpdate(View arg0) {

}

@Override
public void finishUpdate(View arg0) {

}
}
}