从URL下载图片 - Android解析JSON

Question

问题是，当我打开我的活动时显示进度条，while循环连续不断地显示下面的错误代码。 有一类项目，如果你需要更多的代码问评论

public class ImageLoader { 

MemoryCache memoryCache = new MemoryCache(); 
FileCache fileCache; 
private Map<ImageView, String> imageViews = Collections 
     .synchronizedMap(new WeakHashMap<ImageView, String>()); 
ExecutorService executorService; 
// Handler to display images in UI thread 
Handler handler = new Handler(); 

public ImageLoader(Context context) { 
    fileCache = new FileCache(context); 
    executorService = Executors.newFixedThreadPool(5); 
} 

final int stub_id = R.drawable.temp_img; 

public void DisplayImage(String url, ImageView imageView) { 
    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); 

    Bitmap b = decodeFile(f); 
    if (b != null) 
     return b; 

    // Download Images from the Internet 
    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(); 
     conn.disconnect(); 
     bitmap = decodeFile(f); 
     return bitmap; 
    } catch (Throwable ex) { 
     ex.printStackTrace(); 
     if (ex instanceof OutOfMemoryError) 
      memoryCache.clear(); 
     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; 
     FileInputStream stream1 = new FileInputStream(f); 
     BitmapFactory.decodeStream(stream1, null, o); 
     stream1.close(); 

     // Find the correct scale value. It should be the power of 2. 
     // Recommended Size 512 
     final int REQUIRED_SIZE = 70; 
     int width_tmp = o.outWidth, height_tmp = o.outHeight; 
     int scale = 1; 
     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; 
     FileInputStream stream2 = new FileInputStream(f); 
     Bitmap bitmap = BitmapFactory.decodeStream(stream2, null, o2); 
     stream2.close(); 
     return bitmap; 
    } catch (FileNotFoundException e) { 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
    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; 
    } 

    @Override 
    public void run() { 
     try { 
      if (imageViewReused(photoToLoad)) 
       return; 
      Bitmap bmp = getBitmap(photoToLoad.url); 
      memoryCache.put(photoToLoad.url, bmp); 
      if (imageViewReused(photoToLoad)) 
       return; 
      BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad); 
      handler.post(bd); 
     } catch (Throwable th) { 
      th.printStackTrace(); 
     } 
    } 
} 

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(); 
} 

}

07-11 16:33:04.248: W/System.err(2234): java.net.MalformedURLException: Protocol not found: null 
07-11 16:33:04.248: W/System.err(2234):  at java.net.URL.<init>(URL.java:178) 
07-11 16:33:04.248: W/System.err(2234):  at java.net.URL.<init>(URL.java:127) 
07-11 16:33:04.248: W/System.err(2234):  at com.rozajacapp.ImageLoader.getBitmap(ImageLoader.java:66) 
07-11 16:33:04.248: W/System.err(2234):  at com.rozajacapp.ImageLoader.access$0(ImageLoader.java:56) 
07-11 16:33:04.248: W/System.err(2234):  at com.rozajacapp.ImageLoader$PhotosLoader.run(ImageLoader.java:148) 
07-11 16:33:04.248: W/System.err(2234):  at ava.util.concurrent.Executors$RunnableAdapter.call(Executors.java:442) 
07-11 16:33:04.248: 

Answer 1

我建议你使用谷歌排球librairy的HTTP请求。

在这里看到的文档：http://developer.android.com/training/volley/index.html

下载图片的某些代码：

ImageRequest ir = new ImageRequest(url, new Response.Listener<Bitmap>() { 

    @Override 
    public void onResponse(Bitmap response) { 
     iv.setImageBitmap(response); 

    } 
}, 0, 0, null, null); 

RequestQueue rq = Volley.newRequestQueue(this); 
rq.add(ir);