轮播

package com.bwei.viewpager;

import java.util.ArrayList;
import java.util.List;

import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

public class MainActivity extends Activity {
	protected static final String TAG = "MainActivity";
	// 数据源
	private int[] ids = { R.drawable.a, R.drawable.b, R.drawable.c,
			R.drawable.d, R.drawable.e };
	// 集合ImageView
	private List<ImageView> images = new ArrayList<ImageView>();
	private ViewPager vp;
	//创建Handler
  private Handler handler = new Handler();
private MyViewPager viewPager;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		// 找控件
		
		vp = (ViewPager) findViewById(R.id.vp);
		// 获取数据源
		for (int id : ids) {
			ImageView imageView = new ImageView(this);
			imageView.setBackgroundResource(id);
			images.add(imageView);

		}
		//设置适配器
		
		viewPager = new MyViewPager();
		vp.setAdapter(viewPager);

	}

	private class MyViewPager extends PagerAdapter {
		// 获取个数
		@Override
		public int getCount() {
			// TODO Auto-generated method stub
			//return images.size();
			return Integer.MAX_VALUE;
		}

		@Override
		public boolean isViewFromObject(View arg0, Object arg1) {
			// TODO Auto-generated method stub
			return arg0 == arg1;
		}
        //获取viewpager中的子view Item
		@Override
		public Object instantiateItem(ViewGroup container, int position) {
			// TODO Auto-generated method stub
			//position%集合.size
			position %= images.size();
			
			ImageView imageView = images.get(position);			
			vp.addView(imageView);
			return imageView;
			
		}
		//销毁viewpager中子view 
		@Override
		public void destroyItem(ViewGroup container, int position, Object object) {
			// TODO Auto-generated method stub
			//super.destroyItem(container, position, object);
			vp.removeView((View) object);
		}

	}
	//开始轮播
	private void startSwitch(){
	//handler发送延迟消息
		handler.postDelayed(new Runnable() {
			
			@Override
			public void run() {
				// TODO Auto-generated method stub
				//获取当前item
				int currentItem = vp.getCurrentItem();
				Log.i(TAG, "currentItem:"+currentItem);
				//判断是否是最后一个
				/*if(currentItem==viewPager.getCount()-1){
					vp.setCurrentItem(0);
				}else {
					currentItem++;
					vp.setCurrentItem(currentItem);
				}*/
				//循环 播放下一个	
				currentItem++;
				vp.setCurrentItem(currentItem);
				handler.postDelayed(this, 1000);
			}
		}, 1000);
		
	}
	
	private void stopSwitch(){
		handler.removeCallbacksAndMessages(null);
	}
	@Override
	protected void onResume() {
		// TODO Auto-generated method stub
		super.onResume();
		startSwitch();
	}
	@Override
	protected void onPause() {
		// TODO Auto-generated method stub
		super.onPause();
		stopSwitch();
	}

}