Android使用ViewPager实现类似laucher左右拖动效果

<?xml version="1.0" encoding="utf-8"?> 
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent" 
 android:orientation="vertical" > 
 
 <android.support.v4.view.ViewPager 
 android:id="@+id/guidePages" 
 android:layout_width="fill_parent" 
 android:layout_height="wrap_content"/> 
  
 <RelativeLayout 
 android:layout_width="fill_parent" 
 android:layout_height="wrap_content" 
 android:orientation="vertical" > 
 <LinearLayout 
 android:id="@+id/viewGroup" 
 android:layout_width="fill_parent" 
 android:layout_height="wrap_content" 
 android:layout_alignParentBottom="true" 
 android:layout_marginBottom="30dp" 
 android:gravity="center_horizontal" 
 android:orientation="horizontal" > 
 </LinearLayout> 
 </RelativeLayout> 
 
</FrameLayout> 

<?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" > 
 
 <ImageView 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent" 
 android:background="@drawable/feature_guide_0" > 
 </ImageView> 
 
</LinearLayout> 

package com.andyidea.guidedemo; 
 
import java.util.ArrayList; 
 
import android.app.Activity; 
import android.os.Bundle; 
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.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.view.ViewGroup.LayoutParams; 
import android.view.Window; 
import android.widget.ImageView; 
 
public class GuideViewDemoActivity extends Activity { 
 
 private ViewPager viewPager; 
 private ArrayList<View> pageViews; 
 private ViewGroup main, group; 
 private ImageView imageView; 
 private ImageView[] imageViews; 
 
 /** Called when the activity is first created. */ 
 @Override 
 public void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 this.requestWindowFeature(Window.FEATURE_NO_TITLE); 
  
 LayoutInflater inflater = getLayoutInflater(); 
 pageViews = new ArrayList<View>(); 
 pageViews.add(inflater.inflate(R.layout.item01, null)); 
 pageViews.add(inflater.inflate(R.layout.item02, null)); 
 pageViews.add(inflater.inflate(R.layout.item03, null)); 
 pageViews.add(inflater.inflate(R.layout.item04, null)); 
 
 imageViews = new ImageView[pageViews.size()]; 
 main = (ViewGroup)inflater.inflate(R.layout.main, null); 
  
 // group是R.layou.main中的负责包裹小圆点的LinearLayout. 
 group = (ViewGroup)main.findViewById(R.id.viewGroup); 
 
 viewPager = (ViewPager)main.findViewById(R.id.guidePages); 
 
 for (int i = 0; i < pageViews.size(); i++) { 
  imageView = new ImageView(GuideViewDemoActivity.this); 
  imageView.setLayoutParams(new LayoutParams(20,20)); 
  imageView.setPadding(20, 0, 20, 0); 
  imageViews[i] = imageView; 
  if (i == 0) { 
  //默认选中第一张图片 
  imageViews[i].setBackgroundResource(R.drawable.page_indicator_focused); 
  } else { 
  imageViews[i].setBackgroundResource(R.drawable.page_indicator); 
  } 
  group.addView(imageViews[i]); 
 } 
 
 setContentView(main); 
 
 viewPager.setAdapter(new GuidePageAdapter()); 
 viewPager.setOnPageChangeListener(new GuidePageChangeListener()); 
 } 
 
 /** 指引页面Adapter */ 
 class GuidePageAdapter extends PagerAdapter { 
  
 @Override 
 public int getCount() { 
  return pageViews.size(); 
 } 
 
 @Override 
 public boolean isViewFromObject(View arg0, Object arg1) { 
  return arg0 == arg1; 
 } 
 
 @Override 
 public int getItemPosition(Object object) { 
  // TODO Auto-generated method stub 
  return super.getItemPosition(object); 
 } 
 
 @Override 
 public void destroyItem(View arg0, int arg1, Object arg2) { 
  // TODO Auto-generated method stub 
  ((ViewPager) arg0).removeView(pageViews.get(arg1)); 
 } 
 
 @Override 
 public Object instantiateItem(View arg0, int arg1) { 
  // TODO Auto-generated method stub 
  ((ViewPager) arg0).addView(pageViews.get(arg1)); 
  return pageViews.get(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 
 
 } 
 } 
 
 /** 指引页面改监听器 */ 
 class GuidePageChangeListener implements OnPageChangeListener { 
 
 @Override 
 public void onPageScrollStateChanged(int arg0) { 
  // TODO Auto-generated method stub 
 
 } 
 
 @Override 
 public void onPageScrolled(int arg0, float arg1, int arg2) { 
  // TODO Auto-generated method stub 
 
 } 
 
 @Override 
 public void onPageSelected(int arg0) { 
  for (int i = 0; i < imageViews.length; i++) { 
  imageViews[arg0] 
   .setBackgroundResource(R.drawable.page_indicator_focused); 
  if (arg0 != i) { 
   imageViews[i] 
    .setBackgroundResource(R.drawable.page_indicator); 
  } 
  } 
 
 } 
 
 } 
 
}