package asynctask.zb.com.asynctask_02;import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Message;
import android.util.Log;
import android.util.LruCache;
import android.widget.ImageView;import java.io.BufferedInputStream;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;/*** Created by Administrator on 2016/1/20.*/
public class ImageLoader {private ImageView mImageView;private String mUrl;public LruCache<String,Bitmap> mCache;public ImageLoader (){int maxMemory = (int) Runtime.getRuntime().maxMemory();  //获取虚拟机可用内存（内存占用超过该值的时候，将报OOM异常导致程序崩溃）int cacheSzie = maxMemory/4;                            //使用可用内存的1/4来作为Memory CachemCache = new LruCache<String,Bitmap>(cacheSzie) {@Overrideprotected int sizeOf(String key, Bitmap value) {return value.getByteCount(); //返回Bitmap占用的空间，告诉系统我这张图片要用多少内存
            }};}
//把bitmap加入到缓存public void addBitmapToCache(String mUrl, Bitmap bitmap) {if (getBitmapFromCache(mUrl) == null) {mCache.put(mUrl, bitmap);}}
//从缓存中获取数据public Bitmap getBitmapFromCache(String mUrl) {return mCache.get(mUrl);}android.os.Handler mHandler = new android.os.Handler(){@Overridepublic void handleMessage(Message msg) {super.handleMessage(msg);if (mImageView.getTag().equals(mUrl))mImageView.setImageBitmap((Bitmap)msg.obj);}};public void showImageByThread(ImageView imageView, final String url) {mImageView =imageView;mUrl = url;//对传过来的imageView 和url进行缓存（为了避免程序逻辑顺序错误，和viewholder的机制差不多）new Thread() {@Overridepublic void run() {super.run();Bitmap bitmap = getBitmapFromURL(url);Message message = Message.obtain();message.obj = bitmap;mHandler.sendMessage(message);}}.start();}//创建从URL获取Bitmap的放方法public Bitmap getBitmapFromURL(String stringUrl) {Bitmap bitmap;BufferedInputStream bis = null;URL url1 = null;try {url1 = new URL(stringUrl);} catch (MalformedURLException e) {e.printStackTrace();}HttpURLConnection connection = null;try {connection = (HttpURLConnection) url1.openConnection();} catch (IOException e) {e.printStackTrace();}try {bis = new BufferedInputStream(connection.getInputStream());bitmap = BitmapFactory.decodeStream(bis);connection.disconnect();return bitmap;} catch (IOException e) {e.printStackTrace();} finally {try {bis.close();} catch (IOException e) {e.printStackTrace();}}return null;}public void showImageByAsyncTask (ImageView imageView, String url){Bitmap bitmap = getBitmapFromCache(url);if (bitmap == null){new MyIconSyncTask(imageView,url).execute(url);}else{imageView.setImageBitmap(bitmap);}}class MyIconSyncTask extends AsyncTask<String,Void,Bitmap> {private ImageView mImageView;private String mUrl;public MyIconSyncTask(ImageView imageView,String url){mUrl = url;mImageView = imageView;}@Overrideprotected Bitmap doInBackground(String... params) {String mUrl = params[0];//从网络获取图片，并存入缓存中Bitmap bitmap = getBitmapFromURL(mUrl);if (bitmap != null){addBitmapToCache(mUrl,bitmap);}return bitmap;}@Overrideprotected void onPostExecute(Bitmap bitmap) {super.onPostExecute(bitmap);if (mImageView.getTag().equals(mUrl)) {mImageView.setImageBitmap(bitmap);}}}}

package asynctask.zb.com.asynctask_02;import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;import java.net.URL;
import java.util.List;/*** Created by Ace on 2016/1/20.*/
public class NewsAdapter extends BaseAdapter {private List<NewsBean> mlist;private LayoutInflater mInflater;private ImageLoader mImageLoader;public NewsAdapter(Context context,List<NewsBean>data){//映射下 把data传给mlistmlist = data;//从一个上下文中（这里的上下文是MainActivity），获得一个布局填充器，这样你就可以使用这个填充器的inflater.inflate()来把xml布局文件转为View对象了,然后利用view对象，findViewById就可以找到布局中的组件mInflater = LayoutInflater.from(context);mImageLoader = new ImageLoader(); //再适配器初始化ImageLoader
    }@Overridepublic Object getItem(int position) {return mlist.get(position);}@Overridepublic int getCount() {return mlist.size();}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {ViewHolder viewHolder= null;if (convertView == null){viewHolder = new ViewHolder();convertView = mInflater.inflate(R.layout.adapter_item,null);viewHolder.iconimage = (ImageView)convertView.findViewById(R.id.tvimage);viewHolder.title = (TextView)convertView.findViewById(R.id.tvtitle);viewHolder.content = (TextView)convertView.findViewById(R.id.tvcontent);convertView.setTag(viewHolder);}else{viewHolder = (ViewHolder)convertView.getTag();viewHolder.iconimage.setImageResource(R.mipmap.ic_launcher);String   url = mlist.get(position).newsIconUrl;viewHolder.iconimage.setTag(url);//给imageview设置标签 是为了增加一个判断的标准（再imageloader类里），只有URL地址和当前位置的Item的图片相匹配才显示
//            new ImageLoader().showImageByThread(viewHolder.iconimage, mlist.get(position).newsIconUrl);mImageLoader.showImageByAsyncTask(viewHolder.iconimage, mlist.get(position).newsIconUrl);//不能使用 new ImageLoader(). 因为每new一次都创建一个ImageLoader()这样就会有很多的lru
            viewHolder.title.setText(mlist.get(position).newsTitle);viewHolder.content.setText(mlist.get(position).newsContent);}return convertView;}class  ViewHolder{public TextView title;public ImageView iconimage;public TextView content;}
}

private DiskLruCache mDiskLruCache;
private final Object mDiskCacheLock = new Object();//声明锁对象
private boolean mDiskCacheStarting = true;
private static final int DISK_CACHE_SIZE = 1024 * 1024 * 10; // 10MB ，分配Disk内存
private static final String DISK_CACHE_SUBDIR = "thumbnails";//缓存文件夹@Override
protected void onCreate(Bundle savedInstanceState) {...// 初始化memory cache
    ...// 开启后台线程初始化disk cacheFile cacheDir = getDiskCacheDir(this, DISK_CACHE_SUBDIR);//指定缓冲到哪^ ^new InitDiskCacheTask().execute(cacheDir);...
}class InitDiskCacheTask extends AsyncTask<File, Void, Void> {@Overrideprotected Void doInBackground(File... params) {synchronized (mDiskCacheLock) {File cacheDir = params[0];mDiskLruCache = DiskLruCache.open(cacheDir, DISK_CACHE_SIZE);mDiskCacheStarting = false; // 初始化完成mDiskCacheLock.notifyAll(); // 唤醒被hold住的线程
        }return null;}
}class BitmapWorkerTask extends AsyncTask<Integer, Void, Bitmap> {...// 在后台加载图片
    @Overrideprotected Bitmap doInBackground(Integer... params) {final String imageKey = String.valueOf(params[0]);// 通过后台线程检查disk cacheBitmap bitmap = getBitmapFromDiskCache(imageKey);if (bitmap == null) { // 如果没有在disk cache中发现这个bitmap// 加载这个bitmapfinal Bitmap bitmap = decodeSampledBitmapFromResource(getResources(), params[0], 100, 100));}// 把这个bitmap加入cache
        addBitmapToCache(imageKey, bitmap);return bitmap;}...
}public void addBitmapToCache(String key, Bitmap bitmap) {// 把bitmap加入memory cacheif (getBitmapFromMemCache(key) == null) {mMemoryCache.put(key, bitmap);}// 同样，也加入disk cachesynchronized (mDiskCacheLock) {if (mDiskLruCache != null && mDiskLruCache.get(key) == null) {mDiskLruCache.put(key, bitmap);}}
}public Bitmap getBitmapFromDiskCache(String key) {synchronized (mDiskCacheLock) {// 等待disk cache初始化完毕while (mDiskCacheStarting) {try {mDiskCacheLock.wait();} catch (InterruptedException e) {}}if (mDiskLruCache != null) {return mDiskLruCache.get(key);}}return null;
}// 在自带的cache目录下建立一个独立的子目录。优先使用外置存储。但如果外置存储不存在，使用内置存储。
public static File getDiskCacheDir(Context context, String uniqueName) {// 如果MEDIA目录已经挂载或者外置存储是手机自带的（Nexus设备都这么干），使用外置存储；否则使用内置存储final String cachePath =Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState()) ||!isExternalStorageRemovable() ? getExternalCacheDir(context).getPath() :context.getCacheDir().getPath();return new File(cachePath + File.separator + uniqueName);
}

if (tickedCount > 0) { // 如果还有票tickedCount -= 1; // 票数减一printTicket(); // 出票
}

synchronized(this) {if (tickedCount > 0) { // 如果还有票tickedCount -= 1; // 票数减一printTicket(); // 出票
    }
}