package com.android.test;

import java.io.InputStream;

import java.net.HttpURLConnection;

import java.net.URL;

import com.nostra13.universalimageloader.core.ImageLoader;

import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;

import com.nostra13.universalimageloader.core.assist.FailReason;

import com.nostra13.universalimageloader.core.listener.ImageLoadingListener;

import android.app.Activity;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.drawable.BitmapDrawable;

import android.os.AsyncTask;

import android.os.Bundle;

import android.support.v4.util.LruCache;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.ImageView;

import android.widget.ListAdapter;

import android.widget.ListView;

import android.widget.TextView;

public class MainActivity extends Activity {

    private ListView lv_images;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        lv_images = (ListView) findViewById(R.id.lv_images);

        ImageLoaderConfiguration configuration=ImageLoaderConfiguration.createDefault(this);

        ImageLoader.getInstance().init(configuration);

        ListAdapter adapter = new ImageAdapter();

        lv_images.setAdapter(adapter);

    }

    /**

     * 适配器

     * @author taoshihan

     *

     */

    class ImageAdapter extends BaseAdapter {

        private LruCache<String, BitmapDrawable> mImageCache;

        public ImageAdapter() {

            int maxSize=(int) (Runtime.getRuntime().maxMemory()/8);

            mImageCache=new LruCache<String, BitmapDrawable>(maxSize){

                protected int sizeOf(String key, BitmapDrawable drawable) {

                    return drawable.getBitmap().getByteCount();

                };

            };

        }

        @Override

        public View getView(int position, View convertView, ViewGroup parent) {

            String url=(String) getItem(position);

            View view;

            if(convertView!=null){

                view=convertView;

            }else{

                view=View.inflate(getApplicationContext(), R.layout.image_item, null);

            }

            ImageView imageView=(ImageView) view.findViewById(R.id.tv_image);

            BitmapDrawable bitmapDrawable=getBitmapFromMemoryCache(url);

            if(bitmapDrawable!=null){

                //读取缓存图片

                imageView.setImageDrawable(bitmapDrawable);

            }else{

                //读取网络图片

                ImageWorkerTask task=new ImageWorkerTask(imageView);

                task.execute(url);

            }

            return view;

        }

        /**

         * 从缓存中读取图片

         * @param key

         * @return

         */

        public BitmapDrawable getBitmapFromMemoryCache(String key) {

            if(mImageCache.get(key)!=null){

                return mImageCache.get(key);

            }

            return null;

        }

        public void addBitmapToMemoryCache(String key,BitmapDrawable drawable){

            if(getBitmapFromMemoryCache(key)==null){

                mImageCache.put(key, drawable);

            }

        }

        @Override

        public int getCount() {

            // TODO Auto-generated method stub

            return Images.IMAGE_URLS.length;

        }

        @Override

        public Object getItem(int position) {

            return Images.IMAGE_URLS[position];

        }

        @Override

        public long getItemId(int position) {

            // TODO Auto-generated method stub

            return position;

        }

        /**

         * 异步任务

         * @author taoshihan

         *

         */

        class ImageWorkerTask extends AsyncTask<String, Void, BitmapDrawable>{

            private ImageView imageView;

            public ImageWorkerTask(ImageView imageView) {

                this.imageView=imageView;

            }

            @Override

            protected BitmapDrawable doInBackground(String... params) {

                String imageUrl=params[0];

                Bitmap bitmap=downLoadBitmap(imageUrl);

                BitmapDrawable drawable=new BitmapDrawable(getApplicationContext().getResources(),bitmap);

                addBitmapToMemoryCache(imageUrl, drawable);

                return drawable;

            }

            //下载图片

            private Bitmap downLoadBitmap(String imageUrl) {

                Bitmap bitmap=null;

                try {

                    URL url=new URL(imageUrl);

                    HttpURLConnection conn=(HttpURLConnection) url.openConnection();

                    conn.setConnectTimeout(10000);

                    InputStream is=conn.getInputStream();

                    bitmap=BitmapFactory.decodeStream(is);

                } catch (Exception e) {

                }

                return bitmap;

            }

            //下载完成的

            @Override

            protected void onPostExecute(BitmapDrawable result) {

                if(imageView!=null&&result!=null){

                    imageView.setImageDrawable(result);

                }

            }

        }

    }

    static class Images{

        public final static String[] IMAGE_URLS = new String[]{

            "http://img.my.csdn.net/uploads/201508/05/1438760758_3497.jpg",

            "http://img.my.csdn.net/uploads/201508/05/1438760758_6667.jpg",

            "http://img.my.csdn.net/uploads/201508/05/1438760757_3588.jpg",

            "http://img.my.csdn.net/uploads/201508/05/1438760756_3304.jpg",

            "http://img.my.csdn.net/uploads/201508/05/1438760755_6715.jpeg",

            "http://img.my.csdn.net/uploads/201508/05/1438760726_5120.jpg",

            "http://img.my.csdn.net/uploads/201508/05/1438760726_8364.jpg",

            "http://img.my.csdn.net/uploads/201508/05/1438760725_4031.jpg",

            "http://img.my.csdn.net/uploads/201508/05/1438760724_9463.jpg",

            "http://img.my.csdn.net/uploads/201508/05/1438760724_2371.jpg",

            "http://img.my.csdn.net/uploads/201508/05/1438760707_4653.jpg"

        };

    }

}