Android 利用ViewPager实现图片可以左右循环滑动效果附代码下载

 更新时间:2015年11月25日 11:13:33   转载 投稿:mrr  
本文通过一个小demo给大家展示一段代码实现viewpage图片左右循环滑动效果,对viewgager循环滑动相关知识感兴趣的朋友一起学习吧

首先给大家展示靓照,对效果图感兴趣的朋友可以继续往下阅读哦。

ViewPager这个小demo实现的是可以左右循环滑动图片,下面带索引,滑到最后一页在往右滑动就要第一页,第一页往左滑动就到最后一页,上面是效果图,用美女图片是我一贯的作风,呵呵

 1.    首先看一些layout下的xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent" 
 android:orientation="vertical" > 
 <android.support.v4.view.ViewPager 
 android:id="@+id/viewPager" 
 android:layout_width="fill_parent" 
 android:layout_height="wrap_content" /> 
 <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="30dp" 
 android:gravity="center_horizontal" 
 android:orientation="horizontal" > 
 </LinearLayout> 
 </RelativeLayout> 
</FrameLayout> 

使用ViewPager首先需要引入android-support-v4.jar这个jar包。自己不要忘记加

package com.example.viewpagerdemo; 
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.view.ViewGroup.LayoutParams; 
import android.widget.ImageView; 
import android.widget.LinearLayout; 
public class TwoActivity extends Activity implements OnPageChangeListener{ 
 /** 
 * ViewPager 
 */ 
 private ViewPager viewPager; 
 /** 
 * 装点点的ImageView数组 
 */ 
 private ImageView[] tips; 
 /** 
 * 装ImageView数组 
 */ 
 private ImageView[] mImageViews; 
 /** 
 * 图片资源id 
 */ 
 private int[] imgIdArray ; 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 setContentView(R.layout.activity_main); 
 ViewGroup group = (ViewGroup)findViewById(R.id.viewGroup); 
 viewPager = (ViewPager) findViewById(R.id.viewPager); 
 //载入图片资源ID 
 imgIdArray = new int[]{R.drawable.item01, R.drawable.item02, R.drawable.item03, R.drawable.item04, 
 R.drawable.item05,R.drawable.item06, R.drawable.item07, R.drawable.item08}; 
 //将点点加入到ViewGroup中 
 tips = new ImageView[imgIdArray.length]; 
 for(int i=0; i<tips.length; i++){ 
 ImageView imageView = new ImageView(this); 
 imageView.setLayoutParams(new LayoutParams(10,10)); 
 tips[i] = imageView; 
 if(i == 0){ 
 tips[i].setBackgroundResource(R.drawable.page_indicator_focused); 
 }else{ 
 tips[i].setBackgroundResource(R.drawable.page_indicator_unfocused); 
 } 
 LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(new ViewGroup.LayoutParams(LayoutParams.WRAP_CONTENT, 
  LayoutParams.WRAP_CONTENT)); 
 layoutParams.leftMargin = 5; 
 layoutParams.rightMargin = 5; 
 group.addView(imageView, layoutParams); 
 } 
 //将图片装载到数组中 
 mImageViews = new ImageView[imgIdArray.length]; 
 for(int i=0; i<mImageViews.length; i++){ 
 ImageView imageView = new ImageView(this); 
 mImageViews[i] = imageView; 
 imageView.setBackgroundResource(imgIdArray[i]); 
 } 
 //设置Adapter 
 viewPager.setAdapter(new MyAdapter()); 
 //设置监听,主要是设置点点的背景 
 viewPager.setOnPageChangeListener(this); 
 //设置ViewPager的默认项, 设置为长度的100倍,这样子开始就能往左滑动 
 viewPager.setCurrentItem((mImageViews.length) * 100); 
 } 
 /** 
 * 
 * @author xiaanming 
 * 
 */ 
 public class MyAdapter extends PagerAdapter{ 
 @Override 
 public int getCount() { 
 return Integer.MAX_VALUE; 
 } 
 @Override 
 public boolean isViewFromObject(View arg0, Object arg1) { 
 return arg0 == arg1; 
 } 
 @Override 
 public void destroyItem(View container, int position, Object object) { 
 ((ViewPager)container).removeView(mImageViews[position % mImageViews.length]); 
 } 
 /** 
 * 载入图片进去,用当前的position 除以 图片数组长度取余数是关键 
 */ 
 @Override 
 public Object instantiateItem(View container, int position) { 
 ((ViewPager)container).addView(mImageViews[position % mImageViews.length], 0); 
 return mImageViews[position % mImageViews.length]; 
 } 
 } 
 @Override 
 public void onPageScrollStateChanged(int arg0) { 
 } 
 @Override 
 public void onPageScrolled(int arg0, float arg1, int arg2) { 
 } 
 @Override 
 public void onPageSelected(int arg0) { 
 setImageBackground(arg0 % mImageViews.length); 
 } 
 /** 
 * 设置选中的tip的背景 
 * @param selectItems 
 */ 
 private void setImageBackground(int selectItems){ 
 for(int i=0; i<tips.length; i++){ 
 if(i == selectItems){ 
 tips[i].setBackgroundResource(R.drawable.page_indicator_focused); 
 }else{ 
 tips[i].setBackgroundResource(R.drawable.page_indicator_unfocused); 
 } 
 } 
 } 
} 

喜欢的朋友直接下载代码哦。代码下载

上面的代码中,当只有3张图片或者2张图片的时候,滑动存在BUG问题的修改如下

destroyItem(View container, int position, Object object)方法中不removeView

 @Override 
 public void destroyItem(View container, int position, Object object) { 
// ((ViewPager)container).removeView(mImageViews[position % mImageViews.length]); 
 } 
instantiateItem(View container, int position)增加异常扑捉
[java] view plaincopy在CODE上查看代码片派生到我的代码片
@Override 
 public Object instantiateItem(View container, int position) { 
 try { 
 ((ViewPager)container).addView(mImageViews[position % mImageViews.length], 0); 
 }catch(Exception e){ 
 //handler something 
 } 
 return mImageViews[position % mImageViews.length]; 
 } 

以上代码给大家展示了Android 利用ViewPager实现图片可以左右循环滑动效果,希望大家喜欢。

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