通过RadioGroup 和ViewPager 以及Handler 实现图片的轮播

有 四个 知识点 ：

0：ViewPager的PagerAdapter，里面的 list 是使用<Fresco>的 SimpleDreweeView，同时 方法instantiateItem 是 实例化的意思

viewPager = (ViewPager) findViewById(R.id.viewPager);

listUrl = new ArrayList<String>();
listUrl.add("http://fdfs.xmcdn.com/group16/M08/F1/13/wKgDbFal40bR7Uc6AAH3JpWhLiQ015_android_large.jpg");
listUrl.add("http://fdfs.xmcdn.com/group10/M07/F0/14/wKgDaVal9ZLTP5q1AAFIJeYaktQ092_android_large.jpg");
listUrl.add("http://fdfs.xmcdn.com/group12/M07/E8/35/wKgDXFacqEfReClFAAFvbZHe_mU331_android_large.jpg");
listUrl.add("http://fdfs.xmcdn.com/group9/M05/EE/15/wKgDZlagtF_yH9YXAAEyq6YSxDo657_android_large.jpg");
listUrl.add("http://fdfs.xmcdn.com/group11/M07/FC/B4/wKgDbValyzzy0fBpAAMdsEAuI-Q295_android_large.jpg");
listUrl.add("http://fdfs.xmcdn.com/group9/M01/EF/02/wKgDZlaiCqbTzvIzAAH_l7MCT-k503_android_large.jpg");

//获取屏幕的高度,取其三分之一 int height = getWindowManager().getDefaultDisplay().getHeight();
int viewPageHeight = height/3;
ViewGroup.LayoutParams layoutParams = viewPager.getLayoutParams();
layoutParams.height=viewPageHeight;

List<SimpleDraweeView> list = new ArrayList<>();
for(int i = 0; i< listUrl.size(); i++){
    //创建SimpleDraweeView  SimpleDraweeView simpleDraweeView = new SimpleDraweeView(this);
    simpleDraweeView.setImageURI(Uri.parse(listUrl.get(i)));
    simpleDraweeView.setAspectRatio(1.5f);//设置宽高比,记住了,这里是宽高比  simpleDraweeView.setMaxHeight(viewPageHeight);
    simpleDraweeView.getHierarchy().setActualImageScaleType(ScalingUtils.ScaleType.FIT_CENTER);//设置图片居中显示。首先获取它的Hierarchy  list.add(simpleDraweeView);
}
LunboPagerAdapter adapter= new LunboPagerAdapter(list,this);
viewPager.setAdapter(adapter);

---------------------------------------------------------------------------

public class LunboPagerAdapter extends PagerAdapter {

    private List<SimpleDraweeView> list;
    private Context context;

    public LunboPagerAdapter(List<SimpleDraweeView> list, Context context) {
        this.list = list;
        this.context = context;
    }

    @Override
    public int getCount() {
        return list.size();
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
// return false;  return view==object;
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
// return super.instantiateItem(container, position); // View inflate = LayoutInflater.from(context).inflate(R.layout.lunbo_item, container);  container.addView(list.get(position));
        Log.d("160125MY","instantiateItem: position="+position);
        return list.get(position);
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
// super.destroyItem(container, position, object);  container.removeView((View)object);
        Log.d("160125MY","destroyItem: position="+position+" object:"+object.toString());
    }
}

--------------------------------------------------------------------------

使用Fresco 还要创建BaseApplication，然后添加到清单文件中：

public class BaseApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        Fresco.initialize(this);
    }
}

添加到清单文件中

<application  android:name=".BaseApplication"

-------------------------------------------------------------------------

MainActivity：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout  xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:tools="http://schemas.android.com/tools"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:paddingLeft="@dimen/activity_horizontal_margin"  android:paddingRight="@dimen/activity_horizontal_margin"  android:paddingTop="@dimen/activity_vertical_margin"  android:paddingBottom="@dimen/activity_vertical_margin"  tools:context="com.kodulf.lunbodemo.MainActivity"  android:background="@android:color/holo_blue_dark">


        <android.support.v4.view.ViewPager  android:layout_alignParentTop="true"  android:id="@+id/viewPager"  android:background="@android:color/holo_purple"  android:layout_width="wrap_content"  android:layout_height="wrap_content"></android.support.v4.view.ViewPager>
        <RadioGroup  android:layout_alignBottom="@id/viewPager"  android:layout_alignRight="@id/viewPager"  android:layout_marginBottom="20dp"  android:layout_marginRight="50dp"  android:id="@+id/radiogroup"  android:orientation="horizontal"  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:layout_centerHorizontal="true"  >

        </RadioGroup>
</RelativeLayout>

------------------------------------------------------------------------

1：ViewPager 和RadioGroup 的联动，前提是在创建radioButton的时候，添加一个id属性。

 for (int i = 0; i < listUrl.size(); i++) {
            //第一种方式是在代码中创建 // RadioButton radioButton = new RadioButton(this); // radioButton.setId(i); // radioButton.setButtonDrawable(R.drawable.button_selector);   //第二种方法是调用infalter来创建。其实是一个道理。  RadioButton radioButton = (RadioButton)LayoutInflater.from(this).inflate(R.layout.radio_item, null);
            radioButton.setId(i);
            radioGroup.addView(radioButton);
        }
        radioGroup.check(0);
        viewPager.addOnPageChangeListener(this);
        radioGroup.setOnCheckedChangeListener(this);

@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

}
@Override
public void onPageSelected(int position) {
    radioGroup.check(position);
    Log.d("160126MY","viewPager pageSelected position="+position);
}
@Override
public void onPageScrollStateChanged(int state) {
}

@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
    viewPager.setCurrentItem(checkedId);
    Log.d("160126MY","readioGroupChecked checkedId="+checkedId);
}

2：通过handler 实现轮播，就是开辟一个子线程，然后 子线程每sleep（1000）后就执行一次 handler.sentMessage 给主线程的 handler，

在主线程里面，radioGroup.check(i) 就行了

handler = new Handler(){
    @Override
    public void handleMessage(Message msg) {
        super.handleMessage(msg);
        int what = msg.what;
        switch (what){
            case REFRESH:
                int i = msg.arg1;
                radioGroup.check(i);
                Log.d("160126MY","handler arg1 "+i);
                break;
        }
    }
};

        //开辟子线程来实现轮播  thread = new Thread(this);
        thread.start();

@Override
public void run() {
    int i =1;
    while(true){
        Message message = new Message();
        message.what=REFRESH;
        message.arg1=i;
        handler.sendMessage(message);
        Log.d("160126MY","RUN i="+i);
        if(i<listUrl.size())
        {
            i++;
        }
        else{
            i=0;
        }
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

3：RadioButton 的动态生成，

首先需要创建drawable 的

button_selector.xml文件

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

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

<item android:state_checked="true" android:drawable="@drawable/shape_bg"/>

    <item android:drawable="@drawable/shape_bg_notclick"  />

</selector>

还需要创建

shape_bg_notclick。xml

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

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval">

<solid android:color="@android:color/darker_gray"/>

    <size android:height="3dp" android:width="3dp"/>

</shape>

shape_bg。xml

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

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval">

    <solid android:color="@android:color/holo_green_light" />

    <size android:height="3dp" android:width="3dp"/>

</shape>

有两种 方法：1：

for (int i = 0; i < listUrl.size(); i++) {

    //第一种方式是在代码中创建 

 RadioButton radioButton = new RadioButton(this);

    radioButton.setId(i);

    radioButton.setButtonDrawable(R.drawable.button_selector);

    radioGroup.addView(radioButton);

}

第二种方法2：

for (int i = 0; i < listUrl.size(); i++) {

    //第二种方法是调用infalter来创建。其实是一个道理。 

 RadioButton radioButton = (RadioButton)LayoutInflater.from(this).inflate(R.layout.radio_item, null);

    radioButton.setId(i);

    radioGroup.addView(radioButton);

}

第二种方法：需要写一个layout

radio_item.xml

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

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

 android:layout_width="wrap_content" 

 android:layout_height="wrap_content" 

 android:layout_marginRight="20dp" 

 android:layout_marginEnd="20dp" 

 android:button="@drawable/button_selector" 

 >

</RadioButton>

参考：http://www.jb51.net/article/76233.htm

本文实例讲述了JaAndroid实现图片轮播效果代码，分享给大家供大家参考。具体如下：
运行效果截图如下：

具体代码如下：

首先看下一下布局文件：

<RelativeLayout xmlns:android= "http://schemas.android.com/apk/res/android"
 xmlns:tools= "http://schemas.android.com/tools"
 android:layout_width= "match_parent"
 android:layout_height= "match_parent"
 tools:context= ".MainActivity" >

 <!-- 广告条的使用 -->

 <com.xuliugen.viewpager.MyViewPagerTransformerAnim
  android:id= "@+id/viewpager"
  android:layout_width= "match_parent"
  android:layout_height= "200dp" />

 <!-- 广告条下边的文字 -->

 <LinearLayout
  android:layout_width= "match_parent"
  android:layout_height= "wrap_content"
  android:layout_alignBottom= "@id/viewpager"
  android:background= "#33000000"
  android:orientation= "vertical" >

  <TextView
   android:id= "@+id/image_desc"
   android:layout_width= "match_parent"
   android:layout_height= "wrap_content"
   android:gravity= "center"
   android:text= "@string/app_name"
   android:textColor= "@android:color/white"
   android:textSize= "16sp" />

  <LinearLayout
   android:id= "@+id/point_group"
   android:layout_width= "wrap_content"
   android:layout_height= "wrap_content"
   android:layout_gravity= "center_horizontal"
   android:layout_marginBottom= "5dp"
   android:orientation= "horizontal" >
  </LinearLayout>
 </LinearLayout>

</RelativeLayout>

效果很简单，从布局文件中我们看到使用了一个自定义的ViewPager动画，代码如下：

package com.xuliugen.viewpager;

import java.util.HashMap;
import java.util.Map;

import android.content.Context;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.View;

import com.nineoldandroids.view.ViewHelper;

/*
 * 自定义viewpager实现动画切换效果：
 *
 * 1、需要拿到当前切换的两个view
 *
 * 2、一个动画的梯度值
 */
public class MyViewPagerTransformerAnim extends ViewPager {

 private View mLeft;
 private View mRight;

 private float mTrans;
 private float mScale;

 private static final float MIN_SCALE = 0.6f;
 private Map<Integer, View> mChildren = new HashMap<Integer, View>();

 /*
  * 要有两个构造方法
  */
 public MyViewPagerTransformerAnim(Context context, AttributeSet attrs) {
  super(context, attrs);
 }

 public MyViewPagerTransformerAnim(Context context) {
  super(context);
 }

 /*
  * 设置put的方法
  */
 public void setViewForPosition(View view, int position) {
  mChildren.put(position, view);
 }

 /*
  * remove的方法
  */
 public void removeViewFromPosition(Integer position) {
  mChildren.remove(position);
 }

 /**
  * 重写的方法
  */
 @Override
 protected void onPageScrolled( int position, float offset, int offsetPixels) {

  // Log.e("TAG", "position =" + position + ",offset = " + offset);
  mLeft = mChildren.get(position);
  mRight = mChildren.get(position + 1 );

  animStack(mLeft, mRight, offset, offsetPixels); // 创建动画效果

  super .onPageScrolled(position, offset, offsetPixels);
 }

 private void animStack(View left, View right, float offset, int offsetPixels) {
  if (right != null ) {

   // 从0-1页，offset:0`1
   mScale = ( 1 - MIN_SCALE) * offset + MIN_SCALE;

   mTrans = -getWidth() - getPageMargin() + offsetPixels;

   ViewHelper.setScaleX(right, mScale);
   ViewHelper.setScaleY(right, mScale);

   ViewHelper.setTranslationX(right, mTrans);
  }
  if (left != null ) {
   left.bringToFront();
  }
 }
}

MainActivity.java

package com.xuliugen.viewpager;

import java.util.ArrayList;

import android.app.Activity;
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.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MainActivity extends Activity {

 private ViewPager viewPager;

 private LinearLayout pointGroup;

 private TextView iamgeDesc;

 // 图片资源ID
 private final int [] imageIds = { R.drawable.a, R.drawable.b, R.drawable.c,
   R.drawable.d, R.drawable.e };

 // 图片标题集合
 private final String[] imageDescriptions = { "巩俐不低俗，我就不能低俗" ,
   "扑树又回来啦！再唱经典老歌引万人大合唱" , "揭秘北京电影如何升级" , "乐视网TV版大派送" , "热血屌丝的反杀" };

 private ArrayList<ImageView> imageList;

 /**
  * 上一个页面的位置
  */
 protected int lastPosition;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super .onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  viewPager = (ViewPager) findViewById(R.id.viewpager);
  pointGroup = (LinearLayout) findViewById(R.id.point_group);
  iamgeDesc = (TextView) findViewById(R.id.image_desc);
  iamgeDesc.setText(imageDescriptions[ 0 ]);

  imageList = new ArrayList<ImageView>();
  for ( int i = 0 ; i < imageIds.length; i++) {

   // 初始化图片资源
   ImageView image = new ImageView( this );
   image.setBackgroundResource(imageIds[i]);
   imageList.add(image);

   // 添加指示点
   ImageView point = new ImageView( this );
   LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
     LinearLayout.LayoutParams.WRAP_CONTENT,
     LinearLayout.LayoutParams.WRAP_CONTENT);

   params.rightMargin = 20 ;
   point.setLayoutParams(params);

   point.setBackgroundResource(R.drawable.point_bg);
   if (i == 0 ) {
    point.setEnabled( true );
   } else {
    point.setEnabled( false );
   }
   pointGroup.addView(point);
  }

  viewPager.setAdapter( new MyPagerAdapter());

  // viewPager.setCurrentItem(Integer.MAX_VALUE/2 -
  // (Integer.MAX_VALUE/2%imageList.size())) ;

  viewPager.setOnPageChangeListener( new OnPageChangeListener() {

   @Override
   /**
    * 页面切换后调用
    * position 新的页面位置
    */
   public void onPageSelected( int position) {

    position = position % imageList.size();

    // 设置文字描述内容
    iamgeDesc.setText(imageDescriptions[position]);

    // 改变指示点的状态
    // 把当前点enbale 为true
    pointGroup.getChildAt(position).setEnabled( true );
    // 把上一个点设为false
    pointGroup.getChildAt(lastPosition).setEnabled( false );
    lastPosition = position;

   }

   @Override
   /**
    * 页面正在滑动的时候，回调
    */
   public void onPageScrolled( int position, float positionOffset,
     int positionOffsetPixels) {
   }

   @Override
   /**
    * 当页面状态发生变化的时候，回调
    */
   public void onPageScrollStateChanged( int state) {

   }
  });

  /*
   * 自动循环： 1、定时器：Timer 2、开子线程 while true 循环 3、ColckManager 4、 用handler
   * 发送延时信息，实现循环
   */
  isRunning = true;
  // 设置图片的自动滑动
  handler.sendEmptyMessageDelayed(0, 3000);
 }

 /**
  * 判断是否自动滚动
  */
 private boolean isRunning = false;

 private Handler handler = new Handler() {
  public void handleMessage(android.os.Message msg) {

   // 让viewPager 滑动到下一页
   viewPager.setCurrentItem(viewPager.getCurrentItem() + 1);
   if (isRunning) {
    handler.sendEmptyMessageDelayed(0, 3000);
   }
  };
 };

 protected void onDestroy() {

  isRunning = false;
 };

 private class MyPagerAdapter extends PagerAdapter {

  @Override
  /**
   * 获得页面的总数
   */
  public int getCount() {
   return Integer.MAX_VALUE; // 使得图片可以循环
  }

  @Override
  /**
   * 获得相应位置上的view
   * container view的容器，其实就是viewpager自身
   * position  相应的位置
   */
  public Object instantiateItem(ViewGroup container, int position) {

   // System.out.println("instantiateItem ::" + position);

   // 给 container 添加一个view
   container.addView(imageList.get(position % imageList.size()));
   // 返回一个和该view相对的object
   return imageList.get(position % imageList.size());
  }

  @Override
  /**
   * 判断 view和object的对应关系
   */
  public boolean isViewFromObject(View view, Object object) {
   if (view == object) {
    return true;
   } else {
    return false;
   }
  }

  @Override
  /**
   * 销毁对应位置上的object
   */
  public void destroyItem(ViewGroup container, int position, Object object) {
   // System.out.println("destroyItem ::" + position);

   container.removeView((View) object);
   object = null ;
  }
 }

}

另外我们看效果图可以看出，效果图下边的几个原点是变化的，所以我们需要一个selector，如下：

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

 < item android:drawable = "@drawable/point_nomal" android:state_enabled = "false" />
 < item android:drawable = "@drawable/point_focured" android:state_enabled = "true" />

</ selector >

希望本文所述对大家学习Android软件编程有所帮助。