Android 在 ListView 中从 URL 加载图像

Question

我正在从 Rss Xml 文件中读取 imageURL 并在 ListView 中显示，我能够显示图像，但某些图像 URL 出现异常

java.io.FileNotFoundException

这里是我的代码:

public class ImageLoader {

    MemoryCache memoryCache=new MemoryCache();
    FileCache fileCache;
    private Map<ImageView, String> imageViews=Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
    ExecutorService executorService; 
    String type;
    public ImageLoader(Context context,String type){
        fileCache=new FileCache(context);
        executorService=Executors.newFixedThreadPool(5);
        this.type=type;
    } 

    public ImageLoader(Context context){
        fileCache=new FileCache(context);
        executorService=Executors.newFixedThreadPool(5);
    }    
    final int stub_id = R.drawable.toriimg;
    public void DisplayImage(String url, ImageView imageView)
    {
        //Log.d("ImageLoader","Iam in DisplayImage");
        imageViews.put(imageView, url);
        Bitmap bitmap=memoryCache.get(url);
        if(bitmap!=null)
            imageView.setImageBitmap(bitmap);
        else
        {
            queuePhoto(url, imageView);
            imageView.setImageResource(stub_id);           
        }
    }

    private void queuePhoto(String url, ImageView imageView)
    {
        PhotoToLoad p=new PhotoToLoad(url, imageView);
        executorService.submit(new PhotosLoader(p));
    }

    private Bitmap getBitmap(String url) 
    {
        File f=fileCache.getFile(url);

        //from SD cache
        Bitmap b = decodeFile(f);
        if(b!=null)
            return b;

        //from web
        try {
            Bitmap bitmap=null;
            URL imageUrl = new URL(url);
            HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection();
            conn.setConnectTimeout(30000);
            conn.setReadTimeout(30000);
            conn.setInstanceFollowRedirects(true);
            InputStream is=conn.getInputStream();
            OutputStream os = new FileOutputStream(f);
            Utils.CopyStream(is, os);
            os.close();
            bitmap = decodeFile(f);
            return bitmap;
        } catch (Exception ex){
           ex.printStackTrace();
           return null;
        }
    }

    //decodes image and scales it to reduce memory consumption
    private Bitmap decodeFile(File f){
        try {
            //decode image size
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(new FileInputStream(f),null,o);
            //Find the correct scale value. It should be the power of 2.
           int REQUIRED_SIZE=70;
            int width_tmp=o.outWidth, height_tmp=o.outHeight;
            int scale=1;
            if(this.type=="SongPlayActivity")
            {

                scale=1;

            }
            else if(this.type=="AlbumPlayListActivity")
            {


                scale=1;
            }
            else
            {

            while(true){
                if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
                    break;
                width_tmp/=2;
                height_tmp/=2;
                scale*=2;
            }
            }
            //decode with inSampleSize
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize=scale;
            return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
        } catch (FileNotFoundException e) {}
        return null;
    }

    //Task for the queue
    private class PhotoToLoad
    {
        public String url;
        public ImageView imageView;
        public PhotoToLoad(String u, ImageView i){
            url=u; 
            imageView=i;
        }
    }

    class PhotosLoader implements Runnable {
        PhotoToLoad photoToLoad;
        PhotosLoader(PhotoToLoad photoToLoad){
            this.photoToLoad=photoToLoad;
        }

        public void run() {
            if(imageViewReused(photoToLoad))
                return;
            Bitmap bmp=getBitmap(photoToLoad.url);
            memoryCache.put(photoToLoad.url, bmp);
            if(imageViewReused(photoToLoad))
                return;
            BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad);
            Activity a=(Activity)photoToLoad.imageView.getContext();
            a.runOnUiThread(bd);
        }
    }

    boolean imageViewReused(PhotoToLoad photoToLoad){
        String tag=imageViews.get(photoToLoad.imageView);
        if(tag==null || !tag.equals(photoToLoad.url))
            return true;
        return false;
    }

    //Used to display bitmap in the UI thread
    class BitmapDisplayer implements Runnable
    {
        Bitmap bitmap;
        PhotoToLoad photoToLoad;
        public BitmapDisplayer(Bitmap b, PhotoToLoad p){bitmap=b;photoToLoad=p;}
        public void run()
        {
            if(imageViewReused(photoToLoad))
                return;
            if(bitmap!=null)
                photoToLoad.imageView.setImageBitmap(bitmap);
            else
                photoToLoad.imageView.setImageResource(stub_id);
        }
    }

    public void clearCache() {
        memoryCache.clear();
        fileCache.clear();
    }

}

日志:

05-14 13:00:09.640: W/System.err(11295): java.io.FileNotFoundException: http://www.toucheradio.com/hostphotos/kiran Abbaraju.jpg
05-14 13:00:09.640: W/System.err(11295):    at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:521)
05-14 13:00:09.640: W/System.err(11295):    at com.teluguone.torilt.model.ImageLoader.getBitmap(ImageLoader.java:89)
05-14 13:00:09.640: W/System.err(11295):    at com.teluguone.torilt.model.ImageLoader.access$0(ImageLoader.java:72)
05-14 13:00:09.640: W/System.err(11295):    at com.teluguone.torilt.model.ImageLoader$PhotosLoader.run(ImageLoader.java:163)
05-14 13:00:09.640: W/System.err(11295):    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:444)
05-14 13:00:09.640: W/System.err(11295):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
05-14 13:00:09.640: W/System.err(11295):    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
05-14 13:00:09.640: W/System.err(11295):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
05-14 13:00:09.640: W/System.err(11295):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
05-14 13:00:09.640: W/System.err(11295):    at java.lang.Thread.run(Thread.java:1019)

谁能推荐一下？

Answer 1

如日志中所示:

FileNotFoundException: http://www.toucheradio.com/hostphotos/kiran Abbaraju.jpg

您在 url 中传递带有图像名称(kiran Abbaraju.jpg) 的空格，因此在从 url 请求图像之前使用 URLEncoder.encode 对其进行编码:

String img_url="http://www.toucheradio.com/hostphotos/kiran Abbaraju.jpg";
String finalimageurl = URLEncoder.encode(your_img_url,"UTF-8");