Android学习笔记之ViewPager的使用

 使用ViewPager这个类可以轻松实现多个页面的滑动功能，而且相对viewgroup来讲要简单容易一些，在此之前我们需要导入android-support-v4.jar这个jar包，是google提供的扩展包，位置路径为android-sdk-windows\extras\android\support\v4\android-support-v4.jar，如果没有找到，需要打开Android SDK Manager在Extras中进行下载，最后记得引入工程中并build path。

在本示例中，我参考了几个demo整理出来的viewpager的最基本用法，制作了一个类似新闻导航功能的界面，每个页面的下方有对应的项目符号，当页面进行切换的时候项目符号也随之变化，下面是实现后的图片：

java代码：

package com.cogent.viewpager;

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 ViewPagerGuideActivity extends Activity {
    private ViewPager viewPager;
    /**装分页显示的view的数组*/
    private ArrayList<View> pageViews;
    private ImageView imageView;
    /**将小圆点的图片用数组表示*/
    private ImageView[] imageViews;
    //包裹滑动图片的LinearLayout
    private ViewGroup viewPics;
    //包裹小圆点的LinearLayout
    private ViewGroup viewPoints;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);//设置无标题栏
        
        //将要分页显示的View装入数组中
        LayoutInflater inflater = getLayoutInflater();
        pageViews = new ArrayList<View>();
        pageViews.add(inflater.inflate(R.layout.page01, null));
        pageViews.add(inflater.inflate(R.layout.page02, null));
        pageViews.add(inflater.inflate(R.layout.page03, null));
        
        //创建imageviews数组，大小是要显示的图片的数量
        imageViews = new ImageView[pageViews.size()];
        //从指定的XML文件加载视图
        viewPics = (ViewGroup) inflater.inflate(R.layout.view_pics, null);
        
        //实例化小圆点的linearLayout和viewpager
        viewPoints = (ViewGroup) viewPics.findViewById(R.id.viewGroup);
        viewPager = (ViewPager) viewPics.findViewById(R.id.guidePages);
        
        //添加小圆点的图片
        for(int i=0;i<pageViews.size();i++){
            imageView = new ImageView(ViewPagerGuideActivity.this);
            //设置小圆点imageview的参数
            imageView.setLayoutParams(new LayoutParams(20,20));//创建一个宽高均为20 的布局
            imageView.setPadding(20, 0, 20, 0);
            //将小圆点layout添加到数组中
            imageViews[i] = imageView;
            
            //默认选中的是第一张图片，此时第一个小圆点是选中状态，其他不是
            if(i==0){
                imageViews[i].setBackgroundResource(R.drawable.page_indicator_focused);
            }else{
                imageViews[i].setBackgroundResource(R.drawable.page_indicator);
            }
            
            //将imageviews添加到小圆点视图组
            viewPoints.addView(imageViews[i]);
        }
        
        //显示滑动图片的视图
        setContentView(viewPics);
        
        //设置viewpager的适配器和监听事件
        viewPager.setAdapter(new GuidePageAdapter());
        viewPager.setOnPageChangeListener(new GuidePageChangeListener());
    }
    
    
    class GuidePageAdapter extends PagerAdapter{

        //销毁position位置的界面
        @Override
        public void destroyItem(View v, int position, Object arg2) {
            // TODO Auto-generated method stub
            ((ViewPager)v).removeView(pageViews.get(position));
            
        }

        @Override
        public void finishUpdate(View arg0) {
            // TODO Auto-generated method stub
            
        }
        
        //获取当前窗体界面数
        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return pageViews.size();
        }

        //初始化position位置的界面
        @Override
        public Object instantiateItem(View v, int position) {
            // TODO Auto-generated method stub
            ((ViewPager) v).addView(pageViews.get(position));  
            return pageViews.get(position);  
        }

        // 判断是否由对象生成界面
        @Override
        public boolean isViewFromObject(View v, Object arg1) {
            // TODO Auto-generated method stub
            return v == arg1;
        }



        @Override
        public void startUpdate(View arg0) {
            // TODO Auto-generated method stub
            
        }

        @Override
        public int getItemPosition(Object object) {
            // TODO Auto-generated method stub
            return super.getItemPosition(object);
        }

        @Override
        public void restoreState(Parcelable arg0, ClassLoader arg1) {
            // TODO Auto-generated method stub
            
        }

        @Override
        public Parcelable saveState() {
            // TODO Auto-generated method stub
            return null;
        }
    }
    
    
    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 position) {
            // TODO Auto-generated method stub
            for(int i=0;i<imageViews.length;i++){
                imageViews[position].setBackgroundResource(R.drawable.page_indicator_focused);
                //不是当前选中的page，其小圆点设置为未选中的状态
                if(position !=i){
                    imageViews[i].setBackgroundResource(R.drawable.page_indicator);
                }
            }
            
        }
    }   
 }

主页面的布局：

<?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" >

     
    <LinearLayout 

        android:id="@+id/linearLayout1"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:orientation="vertical">
         
        <include layout="@layout/page_header"/>
   
        <android.support.v4.view.ViewPager

            android:id="@+id/guidePages"

            android:layout_width="fill_parent"

            android:layout_height="wrap_content"/>

    </LinearLayout>
    <LinearLayout 

        android:id="@+id/linearLayout2"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:orientation="vertical">

        <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="40dp"

                android:gravity="center_horizontal"

                android:orientation="horizontal">                 

            </LinearLayout>

        </RelativeLayout>

    </LinearLayout>

</FrameLayout>

标题栏的布局：

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:orientation="horizontal"

    android:background="@drawable/title"

    android:gravity="center_vertical" >

    <Button 

        android:id="@+id/btn_left"

        android:layout_width="80dp"

        android:layout_height="30dp"

        android:text="返回"

        android:textSize="15sp"

        android:textColor="@android:color/white"

        android:background="@drawable/header_btn"

        android:layout_margin="5dp"/>

    <TextView 

        android:id="@+id/tvTitle"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="奥运快报"

        android:textSize="18sp"

        android:layout_weight="1"

        android:ellipsize="end"

        android:gravity="center_horizontal"/>

    <Button 

        android:id="@+id/btn_right"

        android:layout_width="80dp"

        android:layout_height="30dp"

        android:text="首页"

        android:textSize="15sp"

        android:textColor="@android:color/white"

        android:background="@drawable/header_btn"

        android:layout_margin="5dp"/> 

</LinearLayout>

子页面的布局：

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical"

    android:background="@android:color/white" >

    <LinearLayout 

        android:layout_width="fill_parent"

        android:layout_height="wrap_content">

    <ImageView 

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:src="@drawable/pic_lindan"/>

    </LinearLayout>

     
    <LinearLayout 

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:layout_marginTop="10dp"

        android:layout_marginBottom="10dp"

        android:layout_marginLeft="30dp"

        android:layout_marginRight="30dp"

        android:background="@drawable/divider_horizontal_line">

    </LinearLayout>

    <LinearLayout 

        android:layout_width="fill_parent"

        android:layout_height="fill_parent">

        <TextView 

            android:layout_width="fill_parent"

            android:layout_height="wrap_content"

            android:layout_marginRight="30dp"

            android:layout_marginLeft="30dp"

            android:textColor="@android:color/black"

            android:text="@string/string_lindan"/>

    </LinearLayout> 

</LinearLayout>

转载自：http://www.cnblogs.com/eyu8874521/archive/2012/08/07/2626455.html

项目源码下载