Android实现广告图片轮播效果

本文实例介绍了Android广告轮播图效果实现方法，分享给大家供大家参考，具体内容如下

首先看下一下布局文件：

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;


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 mChildren = new HashMap();

 
 public MyViewPagerTransformerAnim(Context context, AttributeSet attrs) {
  super(context, attrs);
 }

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

 
 public void setViewForPosition(View view, int position) {
  mChildren.put(position, view);
 }

 
 public void removeViewFromPosition(Integer position) {
  mChildren.remove(position);
 }

 
 @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", "热血考高分的反杀" };

 private ArrayList imageList;

 
 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();
  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
   
   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
   
   public void onPageScrolled(int position, float positionOffset,
     int positionOffsetPixels) {
   }

   @Override
   
   public void onPageScrollStateChanged(int state) {

   }
  });

  
  isRunning = true;
  // 设置图片的自动滑动
  handler.sendEmptyMessageDelayed(0, 3000);
 }

 
 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
  
  public int getCount() {
   return Integer.MAX_VALUE; // 使得图片可以循环
  }

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

  @Override
  
  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：

以上就是本文的全部内容，希望对大家的学习有所帮助。