Android------廣告條

在程序drawable下：

             ---- point_background.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@drawable/point_enable" android:state_enabled="true"></item>
    <item android:drawable="@drawable/point_normal" android:state_enabled="false"></item>

</selector>

======================繪製圖形

point_enable.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
    
    <corners android:radius="5dip"/>
    
    <solid android:color="#aaFFFFFF"/>
</shape>

====================繪製圓點

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
    
    <corners android:radius="5dip"/>
     
    <solid android:color="#55000000"/>
</shape>

package com.example.viewpage;


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

import android.app.Activity;
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.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.LinearLayout.LayoutParams;
import android.widget.TextView;

public class MainActivity extends Activity implements OnPageChangeListener{
	private List<ImageView> listImageViews;
	private String[] imageDescrptions;
	private LinearLayout llPoints;
	private TextView tvTitle;
	private ViewPager mViewPager;
	private int previousPostion=0;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		init();
	}
	
	private void init(){
		mViewPager = (ViewPager) findViewById(R.id.viewpager);
		llPoints = (LinearLayout) findViewById(R.id.ll_points);
		tvTitle = (TextView) findViewById(R.id.tv_title);
		
		listImageViews = new ArrayList<ImageView>();
		
		//初始化圖片的ID，圖片的文本
		int[] imageResIDs=getImageResIDs();
		imageDescrptions=getImageDescriptions();
		
		ImageView mImageView;
		
		View view;
		LayoutParams lp;
		for (int i = 0; i < imageResIDs.length; i++) {
			mImageView = new ImageView(this);
			mImageView.setImageResource(imageResIDs[i]);
			listImageViews.add(mImageView);
			
			//每次循環一次添加一個點
			view=new View(this);
			view.setBackgroundResource(R.drawable.point_background);
			lp= new LayoutParams(5,5);
			lp.leftMargin =	 5 ;
			view.setLayoutParams(lp);
			view.setEnabled(false);
			llPoints.addView(view);
		}
		
		mViewPager.setAdapter(new ViewPagerAdatper());
		int item=Integer.MAX_VALUE/2; 
		mViewPager.setCurrentItem(item);
		
		mViewPager.setOnPageChangeListener(this);
		llPoints.getChildAt(0).setEnabled(true);
		tvTitle.setText(imageDescrptions[0]);
		
		
		previousPostion = item % listImageViews.size();
	}
	/**
	 * 封裝圖片id
	 */
	public int[] getImageResIDs(){
		return new int[]{
				R.drawable.a,
				R.drawable.b,
				R.drawable.c,
				R.drawable.d,
				R.drawable.e
		};
	}
	
	
	public String [] getImageDescriptions(){
		return new String[]{
			"1111111111111111111",
			"2222222222222222222",
			"3333333333333333333"
		};
	}
	/**
	 *ViewPagerAdapter
	 *
	 */
	public class ViewPagerAdatper  extends PagerAdapter{

		/**
		 * viewpager的長度
		 */
		@Override
		public int getCount() {
//			return listImageViews.size();
			return Integer.MAX_VALUE;
		}

		/**
		 * 判斷滑動的控件和將要顯示的控件是否爲同一個
		 * true 直接複用
		 * false 會調用instantiateItem 得到一個新的對象
		 */
		@Override
		public boolean isViewFromObject(View arg0, Object arg1) {
			return arg0 == arg1;
		}
		
		/**
		 * 移除ImageView對象
		 */
		@Override
		public void destroyItem(ViewGroup container, int position, Object object) {
			
//			container.removeView(listImageViews.get(position));	
			mViewPager.removeView(listImageViews.get(position % listImageViews.size()));
			
		}
		
		/**
		 * 得到一個Object對象就是ImageView
		 */
		@Override
		public Object instantiateItem(ViewGroup container, int position) {
//			container.addView(listImageViews.get(position));
//			return listImageViews.get(position);
			
			
			
			// 需要把imageView加到ViewPager中, 把imageView對象返回給上一層
			mViewPager.addView(listImageViews.get(position % listImageViews.size()));
			return listImageViews.get(position % listImageViews.size());
		}
	}
	@Override
	public void onPageScrollStateChanged(int arg0) {
		
	}

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

	/**
	 * 將要出來的item的索引是-1 或者 大於等於 viewpage.getCount()
	 * 不會切換item
	 */
	@Override
	public void onPageSelected(int position) {
		
		int realPosition = position % listImageViews.size();
		
		if(imageDescrptions.length>realPosition){
			// 切換文本顯示的內容
			tvTitle.setText(imageDescrptions[realPosition]);
		}
		// 切換點的狀態
		llPoints.getChildAt(realPosition).setEnabled(true);
		// 把前一個的點置爲false
		llPoints.getChildAt(previousPostion).setEnabled(false);
		
		previousPostion = realPosition;
	}

}

效果圖：