android ViewPager具体解释

    先用图解 ：

    这是一个仿微博界面的xml布局 ，他们之间的关系常常搞混淆，怕记不住 ，总结了几句话：ViewPager里面含界面，它的改变控制（title）Imageview的变化，Textview控制页面，并间接控制Title（imageview）。

   而要做一个完整的denon，其过程例如以下：

1，在xml文件了定义Viewpager，和各种控件。

2，在代码里得到各种控件，并进行对应的浅处理。

3，为Viewpager设置适配器，还有监听器，其它控件也设置对应的监听器。

   记录一个小demo：

package com.example.viewpagerdemo;

import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.DisplayMetrics;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.TranslateAnimation;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

public class WeiBoActivity extends Activity {

	private ViewPager viewPager;//页卡内容
	private ImageView imageView;// 动绘图片
	private TextView textView1,textView2,textView3;
	private List<View> views;// Tab页面列表
	private int offset = 0;// 动绘图片偏移量
	private int currIndex = 0;// 当前页卡编号
	private int bmpW;// 动绘图片宽度
	private View view1,view2,view3;//各个页卡
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.weibo);
		InitImageView();
		InitTextView();
		InitViewPager();
	}

	private void InitViewPager() {
		viewPager=(ViewPager) findViewById(R.id.vPager);
		views=new ArrayList<View>();
		LayoutInflater inflater=getLayoutInflater();
		view1=inflater.inflate(R.layout.lay1, null);
		view2=inflater.inflate(R.layout.lay2, null);
		view3=inflater.inflate(R.layout.lay3, null);
		views.add(view1);
		views.add(view2);
		views.add(view3);
		viewPager.setAdapter(new MyViewPagerAdapter(views));
		viewPager.setCurrentItem(0);
		viewPager.setOnPageChangeListener(new MyOnPageChangeListener());
	}
	 /**
	  *  初始化头标
	  */

	private void InitTextView() {
		textView1 = (TextView) findViewById(R.id.text1);
		textView2 = (TextView) findViewById(R.id.text2);
		textView3 = (TextView) findViewById(R.id.text3);

		textView1.setOnClickListener(new MyOnClickListener(0));
		textView2.setOnClickListener(new MyOnClickListener(1));
		textView3.setOnClickListener(new MyOnClickListener(2));
	}

	/**
	 2      * 初始化动画，这个就是页卡滑动时，以下的横线也滑动的效果，在这里须要计算一些数据
	 3 */

	private void InitImageView() {
		imageView= (ImageView) findViewById(R.id.cursor);
		bmpW = BitmapFactory.decodeResource(getResources(), R.drawable.a).getWidth();// 获取图片宽度
		DisplayMetrics dm = new DisplayMetrics();
		getWindowManager().getDefaultDisplay().getMetrics(dm);
		int screenW = dm.widthPixels;// 获取分辨率宽度
		offset = (screenW / 3 - bmpW) / 2;// 计算偏移量
		Matrix matrix = new Matrix();
		matrix.postTranslate(offset, 0);
		imageView.setImageMatrix(matrix);// 设置动画初始位置
	}
<img src="http://img.my.csdn.net/uploads/201211/10/1352554452_1685.jpg" alt="">
	/** 
	 *     
	 * 头标点击监听 3 */
	private class MyOnClickListener implements OnClickListener{
        private int index=0;
        public MyOnClickListener(int i){
        	index=i;
        }
		public void onClick(View v) {
			viewPager.setCurrentItem(index);			
		}
		
	}
	
	public class MyViewPagerAdapter extends PagerAdapter{
		private List<View> mListViews;
		
		public MyViewPagerAdapter(List<View> mListViews) {
			this.mListViews = mListViews;
		}

		@Override
		public void destroyItem(ViewGroup container, int position, Object object) 	{	
			container.removeView(mListViews.get(position));
		}


		@Override
		public Object instantiateItem(ViewGroup container, int position) {			
			 container.addView(mListViews.get(position), 0);
			 return mListViews.get(position);
		}

		@Override
		public int getCount() {			
			return  mListViews.size();
		}
		
		@Override
		public boolean isViewFromObject(View arg0, Object arg1) {			
			return arg0==arg1;
		}
	}

    public class MyOnPageChangeListener implements OnPageChangeListener{

    	int one = offset * 2 + bmpW;// 页卡1 -> 页卡2 偏移量
		int two = one * 2;// 页卡1 -> 页卡3 偏移量
		public void onPageScrollStateChanged(int arg0) {
			
			
		}

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

		public void onPageSelected(int arg0) {
			/*两种方法，这个是一种，以下另一种，显然这个比較麻烦
			Animation animation = null;
			switch (arg0) {
			case 0:
				if (currIndex == 1) {
					animation = new TranslateAnimation(one, 0, 0, 0);
				} else if (currIndex == 2) {
					animation = new TranslateAnimation(two, 0, 0, 0);
				}
				break;
			case 1:
				if (currIndex == 0) {
					animation = new TranslateAnimation(offset, one, 0, 0);
				} else if (currIndex == 2) {
					animation = new TranslateAnimation(two, one, 0, 0);
				}
				break;
			case 2:
				if (currIndex == 0) {
					animation = new TranslateAnimation(offset, two, 0, 0);
				} else if (currIndex == 1) {
					animation = new TranslateAnimation(one, two, 0, 0);
				}
				break;
				
			}
			*/
			Animation animation = new TranslateAnimation(one*currIndex, one*arg0, 0, 0);//显然这个比較简洁，仅仅有一行代码。
			currIndex = arg0;
			animation.setFillAfter(true);// True:图片停在动画结束位置
			animation.setDuration(300);
			imageView.startAnimation(animation);
			Toast.makeText(WeiBoActivity.this, "您选择了"+ viewPager.getCurrentItem()+"页卡", Toast.LENGTH_SHORT).show();
		}
    	
    }
}

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:id="@+id/linearLayout1"
        android:layout_width="fill_parent"
        android:layout_height="40.0dip"
        android:background="#FFFFFF" >

        <TextView
            android:id="@+id/text1"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:layout_weight="1.0"
            android:gravity="center"
            android:text=" @我"
            android:textColor="#000000"
            android:textSize="20.0dip" />

        <TextView
            android:id="@+id/text2"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:layout_weight="1.0"
            android:gravity="center"
            android:text="评论"
            android:textColor="#000000"
            android:textSize="20.0dip" />

        <TextView
            android:id="@+id/text3"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:layout_weight="1.0"
            android:gravity="center"
            android:text="私信"
            android:textColor="#000000"
            android:textSize="20.0dip" />
    </LinearLayout>

    <ImageView
        android:id="@+id/cursor"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:scaleType="matrix"
        android:src="@drawable/a" />

    <android.support.v4.view.ViewPager
        android:id="@+id/vPager"
        android:layout_width="wrap_content"
        android:layout_height="0dp"
        android:layout_gravity="center"
        android:layout_weight="1.0"
        android:background="#000000"
        android:flipInterval="30"
        android:persistentDrawingCache="animation" />
</LinearLayout>