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);
        }
    }

}