Android开发之欢迎界面标准

 import java.util.ArrayList;
 
 import android.app.Activity;
 import android.content.SharedPreferences;
 import android.os.Bundle;
 import android.support.v4.view.PagerAdapter;
 import android.support.v4.view.ViewPager;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewGroup.LayoutParams;
 
 //安卓应用欢迎界面标准
 public class MainActivity extends Activity {
     private ViewPager viewPager;
     private ViewPagerAdapter pagerAdapter = new ViewPagerAdapter();
     // 欢迎界面显示的视图ID
     private int[] viewsId = { R.layout.wel1, R.layout.wel2, R.layout.wel3 };
     // 缓冲界面显示的视图ID
     private int cacheId = R.layout.wel2;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         SharedPreferences shared = this.getSharedPreferences("app_global",
                 MODE_WORLD_WRITEABLE);
         viewPager = new ViewPager(this);
         viewPager.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
                 LayoutParams.MATCH_PARENT));
         if (!shared.contains("used")) {
             pagerAdapter.setViewsId(viewsId);
             shared.edit().putBoolean("used", true).commit();
         } else {
             pagerAdapter.setViewsId(cacheId);
         }
         viewPager.setAdapter(pagerAdapter);
 
         // 获取最后一个视图，以便绑定事件
         View v = pagerAdapter.getLastView();
 
         setContentView(viewPager);
     }
 
     // 在其中写入当显示缓冲图片时执行的操作
     protected void onShowCachePicture() {
 
     }
 
     private class ViewPagerAdapter extends PagerAdapter {
         private ArrayList<View> viewList = new ArrayList<View>();
 
         @Override
         public void destroyItem(ViewGroup container, int position, Object object) {
             container.removeView(viewList.get(position));
         }
 
         @Override
         public Object instantiateItem(ViewGroup container, int position) {
             container.addView(viewList.get(position));
             return viewList.get(position);
         }
 
         @Override
         public int getCount() {
             return viewList.size();
         }
 
         @Override
         public boolean isViewFromObject(View arg0, Object arg1) {
             return arg0 == arg1;
         }
 
         public void setViewsId(int... ids) {
             LayoutInflater inflater = getLayoutInflater();
             for (int id : ids) {
                 View v = inflater.inflate(id, null);
                 viewList.add(v);
             }
         }
 
         public View getLastView() {
             return viewList.get(viewList.size() - 1);
         }
     }
 
 }