android简单实现轮播图效果
16lz
2021-01-23
利用android的ViewPage实现轮播图效果，ViewPager实现的轮播图广告自定义视图，既支持自动轮播页面也支持手势滑动切换页面。原理也不难，在代码有详细的解释。
一 样式布局文件
<?xml version="1.0" encoding="utf-8"?> 二 实现代码
package com.briup.domain;import java.util.ArrayList;import java.util.List;import java.util.concurrent.Executors;import java.util.concurrent.ScheduledExecutorService;import java.util.concurrent.TimeUnit;import android.content.Context;import android.graphics.drawable.Drawable;import android.os.AsyncTask;import android.os.Handler;import android.os.Message;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.util.AttributeSet;import android.view.LayoutInflater;import android.view.View;import android.widget.FrameLayout;import android.widget.ImageView;import android.widget.ImageView.ScaleType;import android.widget.LinearLayout;import com.briup.iqyuidemo.R;/*import com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator;import com.nostra13.universalimageloader.core.ImageLoader;import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;import com.nostra13.universalimageloader.core.assist.QueueProcessingType;*//** * ViewPager实现的轮播图广告自定义视图； * 既支持自动轮播页面也支持手势滑动切换页面 * * */public class Sildepic extends FrameLayout { //自动轮播的时间间隔 private final static int TIME = 5; //自动轮播启用开关 private final static boolean isAutoPlay = true; private int images[]={R.drawable.iv1,R.drawable.iv2,R.drawable.iv3,R.drawable.iv4,R.drawable.iv5}; //放轮播图片的ImageView 的list private List imageViewsList; //放圆点的View的list private List dotViewsList; private ViewPager viewPager; //当前轮播页 private int currentItem = 0; //定时任务 private ScheduledExecutorService scheduledExecutorService; private Context context; //Handler private Handler handler = new Handler(){ @Override public void handleMessage(Message msg) { // TODO Auto-generated method stub super.handleMessage(msg); viewPager.setCurrentItem(currentItem); } }; public SlideShowView(Context context) { this(context,null); // TODO Auto-generated constructor stub } public SlideShowView(Context context, AttributeSet attrs) { //第一步 this(context, attrs, 0); // TODO Auto-generated constructor stub } public SlideShowView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle);//第二部 this.context = context; initData(); if(isAutoPlay){ startPlay(); } } /** * 开始轮播图切换 */ private void startPlay(){//第四部 scheduledExecutorService = Executors.newSingleThreadScheduledExecutor(); scheduledExecutorService.scheduleAtFixedRate(new SlideShowTask(), 1, TIME, TimeUnit.SECONDS); } /** * 停止轮播图切换 */ private void stopPlay(){ scheduledExecutorService.shutdown(); } /** * 初始化相关Data */ private void initData(){//第三部 imageViewsList = new ArrayList();//存放图片 dotViewsList = new ArrayList();//存放点 initUI(context);//初始化轮播图 } /** * 初始化Views等UI */ private void initUI(Context context){//第五步 LayoutInflater.from(context).inflate(R.layout.layout_slideshow, this, true); LinearLayout dotLayout = (LinearLayout)findViewById(R.id.dotLayout); dotLayout.removeAllViews(); // 热点个数与图片特殊相等 for (int i = 0; i < images.length; i++) { //轮播图初始化 ImageView view = new ImageView(context); view.setBackgroundResource(images[i]); view.setScaleType(ScaleType.FIT_XY); imageViewsList.add(view); //轮播图下边的点初始化 ImageView dotView = new ImageView(context); LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT); params.leftMargin = 4;params.rightMargin = 4;dotLayout.addView(dotView, params); dotViewsList.add(dotView);} viewPager = (ViewPager) findViewById(R.id.viewPager); viewPager.setFocusable(true); viewPager.setAdapter(new MyPagerAdapter()); viewPager.setOnPageChangeListener(new MyPageChangeListener()); } /** * 填充ViewPager的页面适配器 * */ private class MyPagerAdapter extends PagerAdapter{ @Override public void destroyItem(View container, int position, Object object) { ((ViewPager)container).removeView(imageViewsList.get(position)); } @Override public Object instantiateItem(View container, int position) { ImageView imageView = imageViewsList.get(position); ((ViewPager)container).addView(imageViewsList.get(position)); return imageViewsList.get(position); } @Override public int getCount() { // TODO Auto-generated method stub return imageViewsList.size(); } @Override public boolean isViewFromObject(View arg0, Object arg1) { // TODO Auto-generated method stub return arg0 == arg1; } @Override public void restoreState(Parcelable arg0, ClassLoader arg1) { // TODO Auto-generated method stub } @Override public Parcelable saveState() { // TODO Auto-generated method stub return null; } @Override public void startUpdate(View arg0) { // TODO Auto-generated method stub } @Override public void finishUpdate(View arg0) { // TODO Auto-generated method stub } } /** * ViewPager的监听器 * 当ViewPager中页面的状态发生改变时调用 * */ private class MyPageChangeListener implements OnPageChangeListener{ boolean isAutoPlay = false; @Override public void onPageScrollStateChanged(int arg0) { // TODO Auto-generated method stub switch (arg0) { case 1:// 手势滑动，空闲中 isAutoPlay = false; break; case 2:// 界面切换中 isAutoPlay = true; break; case 0:// 滑动结束，即切换完毕或者加载完毕 // 当前为最后一张，此时从右向左滑，则切换到第一张 if (viewPager.getCurrentItem() == viewPager.getAdapter().getCount() - 1 && !isAutoPlay) { viewPager.setCurrentItem(0); } // 当前为第一张，此时从左向右滑，则切换到最后一张 else if (viewPager.getCurrentItem() == 0 && !isAutoPlay) { viewPager.setCurrentItem(viewPager.getAdapter().getCount() - 1); } break; } } @Override public void onPageScrolled(int arg0, float arg1, int arg2) { // TODO Auto-generated method stub } @Override public void onPageSelected(int pos) { // TODO Auto-generated method stub currentItem = pos; for(int i=0;i < dotViewsList.size();i++){ if(i == pos){ ((View)dotViewsList.get(pos)).setBackgroundResource(R.drawable.dot_focus); }else { ((View)dotViewsList.get(i)).setBackgroundResource(R.drawable.dot_blur); } } } } /** *执行轮播图切换任务 * */ private class SlideShowTask implements Runnable{ @Override public void run() { // TODO Auto-generated method stub synchronized (viewPager) { //循环轮播 currentItem = (currentItem+1)%imageViewsList.size(); handler.obtainMessage().sendToTarget(); } } } /** * 销毁ImageView资源，回收内存 * */ private void destoryBitmaps() { for (int i = 0; i < images.length; i++) { ImageView imageView = imageViewsList.get(i); Drawable drawable = imageView.getDrawable(); if (drawable != null) { //解除drawable对view的引用 drawable.setCallback(null); } } }} 
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