Android图片异步加载，,import java.

Android图片异步加载，,import java.

import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.InputStream;import java.io.OutputStream;import java.lang.ref.SoftReference;import java.net.HttpURLConnection;import java.net.URL;import java.util.HashMap;import java.util.Map;import com.mosjoy.ad.MosJoyAdApplication;import com.mosjoy.ad.R;import com.mosjoy.ad.utils.FileCache;import com.mosjoy.ad.utils.ImageCache;import com.mosjoy.ad.utils.Utils;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.AsyncTask;import android.os.Environment;import android.os.StatFs;import android.util.AttributeSet;import android.util.Log;import android.view.View;import android.widget.ImageView;/** * 图片异步加载工具类 * @author zouyb * */public class RemoteImageView extends ImageView {    /**     * 下载失败最大重复次数     */    private static int MAX_FAILURES = 3;    /**     * 下载图片网址     */    private String mUrl;    /**     * 当前下载成功图片网址     */    private String mCurrentlyGrabbedUrl;    /**     * 下载失败次数     */    private int mFailure;    /**     * 默认图片资源id     */    private Integer mDefaultImage;    /**     * 上下文     */    private Context mContext;    /**     *  文件操作     */    private FileCache fileCache;    private final static int MB = 1048576;    //图片宽度    private int pwidth=-1;    //图片高度    private int pheight=-1;    //是否显示默认图片    private boolean isShowDefault=false;    public RemoteImageView(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        mContext = context;        init();    }    public RemoteImageView(Context context, AttributeSet attrs) {        super(context, attrs);        mContext = context;        init();    }    public RemoteImageView(Context context) {        super(context);        mContext = context;        init();    }    /**     * Sharable code between constructors     */    private void init() {        fileCache = new FileCache(mContext);    }    public void setImageUrl(String url) {        System.out.println("width="+pwidth+",height="+pheight);        System.out.println("url="+url);        if(("").equals(url) || url == null||url.contains("null")){            if(isShowDefault){                setImageResource(R.drawable.default_image);            }else{                setVisibility(View.GONE);            }            return;        }        setVisibility(View.VISIBLE);        url = url.replace("\\", "/");        mUrl = url;        MosJoyAdApplication instance = MosJoyAdApplication.getInstance();        ImageCache imageCache = instance.getImageCache();        if (imageCache.isCached(mUrl)) {            // 图片在缓存中            this.setImageBitmap(imageCache.get(mUrl).get());            Log.e(MosJoyAdApplication.TAG, "从内存加载图片 " + url);        } else {            File f = new File(mUrl);            Bitmap b = decodeFile(f);            if(b != null){                //从内存卡加载                this.setImageBitmap(b);                imageCache.put(mUrl,new SoftReference<Bitmap>(b));                Log.e(MosJoyAdApplication.TAG, "从本地加载图片 " + url);            }else{                //防止重复下载                //if(YYQMusicApplication.getInstance().getDownLoadImageList().contains(mUrl)) return;                //下载图片                Log.e(MosJoyAdApplication.TAG, "从网络下载图片 " + url);                Map<String,Object> map = new HashMap<String,Object>();                map.put("url", mUrl);                map.put("file", f);                try{                    new DownloadTask().execute(map);                }catch(Exception e){}            }        }    }    public void setDefaultImage(Integer resid) {        mDefaultImage = resid;    }    private void loadDefaultImage() {        if (mDefaultImage != null)            setImageResource(mDefaultImage);    }    class DownloadTask extends AsyncTask<Map<String, Object>,Void, Bitmap>{        private String mTaskUrl;        private File f;        @Override        public void onPreExecute() {            loadDefaultImage();            super.onPreExecute();        }        @Override        protected Bitmap doInBackground(Map<String, Object>... params) {            mTaskUrl = params[0].get("url").toString();            //YYQMusicApplication.getInstance().getDownLoadImageList().add(mTaskUrl);            f = (File) params[0].get("file");            try {                Bitmap bitmap=null;                URL imageUrl = new URL(mTaskUrl);                HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection();                conn.setConnectTimeout(30000);                conn.setReadTimeout(30000);                InputStream is=conn.getInputStream();                OutputStream os = new FileOutputStream(f);                Utils.CopyStream(is, os);                os.close();                bitmap = decodeFile(f);                return bitmap;            } catch(FileNotFoundException fileNotFoundException){                fileNotFoundException.printStackTrace();                return null;            }            catch (Exception ex){               ex.printStackTrace();            }            return null;        }        @Override        public void onPostExecute(Bitmap b) {            super.onPostExecute(b);            if(b == null){                //下载失败，继续下载                //RemoteImageView.this.setImageUrl(mTaskUrl);            }else{                //下载成功                MosJoyAdApplication.getInstance().getImageCache().put(mTaskUrl, new SoftReference<Bitmap>(b));                RemoteImageView.this.setImageBitmap(b);                            mCurrentlyGrabbedUrl = mTaskUrl;                           }        }    };    /**     * 解码图片     * @param f     * @return     */    private Bitmap decodeFile(File f) {        if(!f.exists()){            return null;        }        if(pwidth>0&amp;&amp;pheight>0){            System.out.println("加载缩略图");            return decodeFile(f, pwidth, pheight);        }        try {            BitmapFactory.Options options = new BitmapFactory.Options();            options.inSampleSize = 1;            return BitmapFactory.decodeFile(f.getAbsolutePath(), options);        } catch (Exception e) {        }        return null;    }    private int freeSpaceOnSd() {        StatFs stat = new StatFs(Environment.getExternalStorageDirectory()                .getPath());        double sdFreeMB = ((double) stat.getAvailableBlocks() * (double) stat                .getBlockSize()) / MB;        return (int) sdFreeMB;    }    private Bitmap decodeFile(File file,int width,int height){        BitmapFactory.Options options=new BitmapFactory.Options();        int scale=1;        if(width>0||height>0){            //设置次参数为true，解码时返回的Bitmap为空，不分配内存            options.inJustDecodeBounds=true;            BitmapFactory.decodeFile(file.getAbsolutePath(), options);            //得到原始图片的宽度和高度            int outWidth=options.outWidth;            int outHeight=options.outHeight;            while(true){                if((width>0&amp;&amp;outWidth/2<width)||(height>0&amp;&amp;outHeight/2<height)){                    break;                }                outWidth/=2;                outHeight/=2;                scale*=2;            }        }        //缩放比例为1/scale        options.inSampleSize=scale;        options.inJustDecodeBounds=false;        //处理之后，加载进内存的就是图片的缩略图        return BitmapFactory.decodeFile(file.getAbsolutePath(), options);    }    public void setPwidth(int pwidth) {        this.pwidth = pwidth;    }    public void setPheight(int pheight) {        this.pheight = pheight;    }    public void setShowDefault(boolean isShowDefault) {        this.isShowDefault = isShowDefault;    }}