• 【Android】android图片轮播


    第一步,先写布局文件


    <com.main.util.SlideShowView 
                    android:id="@+id/slideshowView"
                    android:layout_width="fill_parent"
                    android:layout_height="300dp"
                    android:layout_centerHorizontal="true"
                    />


    第二步,java代码


    package com.main.util;
    
    import java.util.ArrayList;
    import java.util.List;
    import java.util.concurrent.Executors;
    import java.util.concurrent.ScheduledExecutorService;
    import java.util.concurrent.TimeUnit;
    
    import com.main.R;
    
    import android.content.Context;
    import android.graphics.drawable.Drawable;
    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;
    
    
    public class SlideShowView extends FrameLayout {
    	//轮播图图片数量
        private final static int IMAGE_COUNT = 5;
        //自动轮播的时间间隔
        private final static int TIME_INTERVAL = 5;
        //自动轮播启用开关
        private final static boolean isAutoPlay = true; 
        
        //自定义轮播图的资源ID
        private int[] imagesResIds;
        //放轮播图片的ImageView 的list
        private List<ImageView> imageViewsList;
        //放圆点的View的list
        private List<View> dotViewsList;
        
        private ViewPager viewPager;
        //当前轮播页
        private int currentItem  = 0;
        //定时任务
        private ScheduledExecutorService scheduledExecutorService;
        //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) {
            this(context, attrs, 0);
            // TODO Auto-generated constructor stub
        }
        public SlideShowView(Context context, AttributeSet attrs, int defStyle) {
            super(context, attrs, defStyle);
            // TODO Auto-generated constructor stub
            initData();
            initUI(context);
            if(isAutoPlay){
                startPlay();
            }
            
        }
        /**
         * 开始轮播图切换
         */
        private void startPlay(){
            scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();
            scheduledExecutorService.scheduleAtFixedRate(new SlideShowTask(), 1, 4, TimeUnit.SECONDS);
        }
        /**
         * 停止轮播图切换
         */
        private void stopPlay(){
            scheduledExecutorService.shutdown();
        }
        /**
         * 初始化相关Data
         */
        private void initData(){
            imagesResIds = new int[]{//图片数据
                    R.drawable.p1,  
                    R.drawable.p2,
            };
            imageViewsList = new ArrayList<ImageView>();
            dotViewsList = new ArrayList<View>();
            
        }
        /**
         * 初始化Views等UI
         */
        private void initUI(Context context){
            LayoutInflater.from(context).inflate(R.layout.imageviewpager, this, true);
            for(int imageID : imagesResIds){
                ImageView view =  new ImageView(context);
                view.setImageResource(imageID);
                view.setScaleType(ScaleType.FIT_XY);
                imageViewsList.add(view);
            }
            dotViewsList.add(findViewById(R.id.v_dot1));
            dotViewsList.add(findViewById(R.id.v_dot2));
            
            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
         * @author caizhiming
         */
        private class MyPagerAdapter  extends PagerAdapter{
    
            @Override
            public void destroyItem(View container, int position, Object object) {
                // TODO Auto-generated method stub
                //((ViewPag.er)container).removeView((View)object);
                ((ViewPager)container).removeView(imageViewsList.get(position));
            }
    
            @Override
            public Object instantiateItem(View container, int position) {
                // TODO Auto-generated method stub
                ((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
         * @author caizhiming
         */
        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_black);
                    }else {
                        ((View)dotViewsList.get(i)).setBackgroundResource(R.drawable.dot_white);
                    }
                }
            }
            
        }
        
        /**
         *执行轮播图切换任务
         *@author caizhiming
         */
        private class SlideShowTask implements Runnable{
    
            @Override
            public void run() {
                // TODO Auto-generated method stub
                synchronized (viewPager) {
                    currentItem = (currentItem+1)%imageViewsList.size();
                    handler.obtainMessage().sendToTarget();
                }
            }
            
        }
        /**
         * 销毁ImageView资源,回收内存
         * @author caizhiming
         */
        private void destoryBitmaps() {
    
            for (int i = 0; i < IMAGE_COUNT; 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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  • 原文地址:https://www.cnblogs.com/shipeng22022/p/4613979.html
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