Android 使用ViewPager實現左右迴圈滑動圖片

標籤：

ViewPager這個小demo實現的是可以左右迴圈滑動圖片，下面帶索引，滑到最後一頁在往右滑動就要第一頁，第一頁往左滑動就到最後一頁，先上，用美女圖片是我一貫的作風，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這個jar包。自己不要忘記加

 

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;/** * 裝點點的ImageView數組 */private ImageView[] tips;/** * 裝ImageView數組 */private ImageView[] mImageViews;/** * 圖片資源id */private int[] imgIdArray ;@Overrideprotected 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);//載入圖片資源IDimgIdArray = 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};//將點點加入到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);}//將圖片裝載到數組中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]);}//設定AdapterviewPager.setAdapter(new MyAdapter());//設定監聽，主要是設定點點的背景viewPager.setOnPageChangeListener(this);//設定ViewPager的預設項, 設定為長度的100倍，這樣子開始就能往左滑動viewPager.setCurrentItem((mImageViews.length) * 100);}/** *  * @author xiaanming * */public class MyAdapter extends PagerAdapter{@Overridepublic int getCount() {return Integer.MAX_VALUE;}@Overridepublic boolean isViewFromObject(View arg0, Object arg1) {return arg0 == arg1;}@Overridepublic void destroyItem(View container, int position, Object object) {((ViewPager)container).removeView(mImageViews[position % mImageViews.length]);}/** * 載入圖片進去，用當前的position 除以 圖片數組長度取餘數是關鍵 */@Overridepublic Object instantiateItem(View container, int position) {((ViewPager)container).addView(mImageViews[position % mImageViews.length], 0);return mImageViews[position % mImageViews.length];}}@Overridepublic void onPageScrollStateChanged(int arg0) {}@Overridepublic void onPageScrolled(int arg0, float arg1, int arg2) {}@Overridepublic void onPageSelected(int arg0) {setImageBackground(arg0 % mImageViews.length);}/** * 設定選中的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);}}}}

 

代碼下載

 

上面的代碼中，當只有3張圖片或者2張圖片的時候，滑動存在BUG問題的修改如下

 

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

 

 

@Overridepublic void destroyItem(View container, int position, Object object) {//((ViewPager)container).removeView(mImageViews[position % mImageViews.length]);}

 

• instantiateItem(View container, int position)增加異常撲捉

 

 

@Overridepublic 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];}

 

 

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Android 使用ViewPager實現左右迴圈滑動圖片