ViewPager实现轮播图和小圆点

有一些bug。

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

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
import android.widget.LinearLayout;
import android.widget.RadioGroup;

public class SplashActivity extends Activity {

	ViewPager vp;
	RadioGroup rg;
	Button btn;
	
	LinearLayout ll;
	//把小圆点存到集合中
	List listDoc;

	List list;
	int[] imgArray = { R.drawable.guide1, R.drawable.guide2, R.drawable.guide3, R.drawable.ic_launcher };

	int count = 0;
	Handler handler = new Handler(){
		public void handleMessage(android.os.Message msg) {
			count++;
			vp.setCurrentItem(count);
			sendEmptyMessageDelayed(0, 1000);
		};
	};
	
	SharedPreferences preferences;
	Editor editor;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_splash);
		
		//当该acitivty启动的时候，先从SharedPreferences中获取登录状态的值，如果为true，那么直接调转到主页
		preferences = getSharedPreferences("state", MODE_PRIVATE);
		if(preferences.getBoolean("isLogin", false)){
			Intent intent = new Intent(SplashActivity.this, MainActivity.class);
			startActivity(intent);
			finish();
		}

//		rg = (RadioGroup) findViewById(R.id.rg);
		btn = (Button) findViewById(R.id.btn);

		// 1、初始化控件
		vp = (ViewPager) findViewById(R.id.vp);
		// 2、初始化数据
		initData();
		// 3、创建apdater对象
		MyPagerAdapter adapter = new MyPagerAdapter();
		// 4、绑定
		vp.setAdapter(adapter);
		
		//添加小圆点的方法
		addDoc();
		
		btn.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				//当点击按钮后  说明已经进入到了主页，所以把登录状态修改成true
//				editor = preferences.edit();
//				editor.putBoolean("isLogin", true);
//				//编辑设置数据后 必须要提交
//				editor.commit();
				
				Intent intent = new Intent(SplashActivity.this, MainActivity.class);
				startActivity(intent);
				finish();
			}
		});
		
		handler.sendEmptyMessageDelayed(0, 1000);

		vp.setOnPageChangeListener(new OnPageChangeListener() {

			@Override
			public void onPageSelected(int arg0) {
				// 通过vp的选中位置，来确定小圆点的联动
				int index = arg0 % list.size();
				for (int i = 0; i < imgArray.length; i++) {
					if(index == i){
						listDoc.get(i).setImageResource(R.drawable.point_selected);
					}else{
						listDoc.get(i).setImageResource(R.drawable.point_mormal);
					}
				}
				//当index == 3的时候 说明显示的是第四张图片
				if(index == imgArray.length - 1){
					btn.setVisibility(View.VISIBLE);
				}else{
					btn.setVisibility(View.GONE);
				}
//				switch (index) {
//				case 0:
//					rg.check(R.id.rb1);
//					btn.setVisibility(View.GONE);
//					break;
//				case 1:
//					rg.check(R.id.rb2);
//					btn.setVisibility(View.GONE);
//					break;
//				case 2:
//					rg.check(R.id.rb3);
//					btn.setVisibility(View.VISIBLE);
//					break;
//				default:
//					break;
//				}
			}

			@Override
			public void onPageScrolled(int arg0, float arg1, int arg2) {
				// TODO Auto-generated method stub

			}

			@Override
			public void onPageScrollStateChanged(int arg0) {
				// TODO Auto-generated method stub

			}
		});
	}
	
	/**
	 * 把小圆点按照导航图片的数量初始化出来
	 */
	private void addDoc() {
		listDoc = new ArrayList();
		ll = (LinearLayout) findViewById(R.id.ll);
		
		//根据图片的数量创建小圆点对象
		for (int i = 0; i < imgArray.length; i++) {
			ImageView iv = new ImageView(SplashActivity.this);
			if(i == 0){
				iv.setImageResource(R.drawable.point_selected);
			}else{
				iv.setImageResource(R.drawable.point_mormal);
			}
			listDoc.add(iv);
			ll.addView(iv);
		}
	}


	@Override
	protected void onStop() {
		//重写stop声明周期方法
		//当点击按钮执行页面跳转时，欢迎页会被关闭，那么handler的消息不会随着acitivy的关闭而停止，所以需要手动移除消息
		if(handler != null){
			handler.removeMessages(0);
		}
		super.onStop();
	}
	

	private void initData() {
		list = new ArrayList();
		for (int i = 0; i < imgArray.length; i++) {
			ImageView iv = new ImageView(SplashActivity.this);
			iv.setImageResource(imgArray[i]);
			iv.setScaleType(ScaleType.FIT_XY);

			list.add(iv);
		}
	}

	class MyPagerAdapter extends PagerAdapter {

		@Override
		public int getCount() {
			return Integer.MAX_VALUE;
		}

		@Override
		public boolean isViewFromObject(View arg0, Object arg1) {
			// TODO Auto-generated method stub
			return arg0 == arg1;
		}

		@Override
		public void destroyItem(ViewGroup container, int position, Object object) {
			// TODO Auto-generated method stub
			container.removeView((View) object);
		}

		@Override
		public Object instantiateItem(ViewGroup container, int position) {
			// 因为是无限轮播 所以position参数会一直增长
			// 那么我需要对list集合的长度取余数得到一个index下标
			int index = position % list.size();
			container.addView(list.get(index));
			return list.get(index);
		}

	}

}