從服務器下載Android圖像？

Question

my logcat---------:: 


09-07 19:55:51.623: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:55:51.634: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:55:52.033: DEBUG/dalvikvm(1680): GC_FOR_MALLOC freed 1896 objects/518112 bytes in 97ms 
09-07 19:55:52.364: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:55:53.254: DEBUG/dalvikvm(1680): GC_FOR_MALLOC freed 822 objects/539696 bytes in 67ms 
09-07 19:56:01.514: INFO/System.out(1680): ImageUrl :: http://www.heresmyparty.com/cms/components/com_chronocontact/uploads/add_event_form/20110805085124_wtpa.logo.png 
09-07 19:56:01.584: INFO/System.out(1680): ImageUrl :: http://www.heresmyparty.com/cms/components/com_chronocontact/uploads/add_event_form/20110805084621_wtpa.logo.png 
09-07 19:56:01.643: INFO/System.out(1680): ImageUrl :: http://www.heresmyparty.com/cms/components/com_chronocontact/uploads/add_event_form/20110805025050_chuckie liv.ashx.jpg 
09-07 19:56:01.684: INFO/System.out(1680): ImageUrl :: http://www.heresmyparty.com/cms/components/com_chronocontact/uploads/add_event_form/20110805024007_space vegas.ashx.jpg 
09-07 19:56:01.914: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:56:01.953: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:56:02.714: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:56:02.754: INFO/System.out(1680): ImageUrl :: http://www.heresmyparty.com/cms/components/com_chronocontact/uploads/add_event_form/20110805023407_blush vegas.ashx.jpg 
09-07 19:56:02.834: INFO/System.out(1680): ImageUrl :: http://www.heresmyparty.com/cms/components/com_chronocontact/uploads/add_event_form/20110805022856_Savoy vegas.ashx.jpg 
09-07 19:56:02.944: DEBUG/dalvikvm(1680): GC_FOR_MALLOC freed 1058 objects/490016 bytes in 80ms 
09-07 19:56:02.944: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:56:02.944: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:56:03.894: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:56:03.923: INFO/System.out(1680): ImageUrl :: http://www.heresmyparty.com/cms/components/com_chronocontact/uploads/add_event_form/20110808101519_DSC0028-Ti.jpg 
09-07 19:56:04.104: INFO/System.out(1680): ImageUrl :: http://www.heresmyparty.com/cms/components/com_chronocontact/uploads/add_event_form/20110729152914_wtpa.logo.png 
09-07 19:56:04.604: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:56:04.634: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:56:05.004: DEBUG/dalvikvm(1680): GC_FOR_MALLOC freed 966 objects/515008 bytes in 80ms 
09-07 19:56:05.404: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:56:05.434: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:56:05.464: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 
09-07 19:56:06.194: DEBUG/skia(1680): --- SkImageDecoder::Factory returned null 

我的代碼::

import java.io.BufferedInputStream; 
import java.io.BufferedOutputStream; 
import java.io.ByteArrayOutputStream; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.OutputStream; 
import java.net.HttpURLConnection; 
import java.net.URI; 
import java.net.URISyntaxException; 
import java.net.URL; 
import java.net.URLDecoder; 
import java.net.URLEncoder; 
import java.util.Collections; 
import java.util.Map; 
import java.util.Stack; 
import java.util.WeakHashMap; 

import org.apache.http.HttpEntity; 
import org.apache.http.HttpResponse; 
import org.apache.http.client.HttpClient; 
import org.apache.http.client.methods.HttpGet; 
import org.apache.http.entity.BufferedHttpEntity; 
import org.apache.http.impl.client.DefaultHttpClient; 

import android.app.Activity; 
import android.content.Context; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.util.EventLogTags.Description; 
import android.view.View; 
import android.widget.ImageView; 
import android.widget.ProgressBar; 

public class ImageLoader { 

    MemoryCache memoryCache = new MemoryCache(); 
    FileCache fileCache; 
    private Map<ImageView, String> imageViews = Collections 
      .synchronizedMap(new WeakHashMap<ImageView, String>()); 
    private ProgressBar indicator; 

    public ImageLoader(Context context) { 

     photoLoaderThread.setPriority(Thread.NORM_PRIORITY - 1); 
     fileCache = new FileCache(context); 
    } 

    public void DisplayImage(String url, Context activity, ImageView imageView, 
      ProgressBar pbar) { 

     imageViews.put(imageView, url); 
     Bitmap bitmap = memoryCache.get(url); 

     if (bitmap != null) { 
      this.indicator = pbar; 
      indicator.setVisibility(View.INVISIBLE); 
      imageView.setImageBitmap(bitmap); 
     } else { 
      this.indicator = pbar; 
      indicator.setVisibility(View.INVISIBLE); 
      queuePhoto(url, activity, imageView); 
      imageView.setImageBitmap(null); 
     } 
    } 

    private void queuePhoto(String url, Context activity, ImageView imageView) { 
     // This ImageView may be used for other images before. So there may be 
     // some old tasks in the queue. We need to discard them. 
     photosQueue.Clean(imageView); 
     PhotoToLoad p = new PhotoToLoad(url, imageView); 
     synchronized (photosQueue.photosToLoad) { 
      photosQueue.photosToLoad.push(p); 
      photosQueue.photosToLoad.notifyAll(); 
     } 

     // start thread if it's not started yet 
     if (photoLoaderThread.getState() == Thread.State.NEW) 
      photoLoaderThread.start(); 
    } 

    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 { 

      HttpGet httpRequest = null; 

      try { 


       int pos = url.lastIndexOf('/') + 1; 
       URI uri = new URI(url.substring(0, pos) 
         + URLEncoder.encode(url.substring(pos), "UTF-8")); 
       //URL imgUrl = new URL(decodeUrl); 
       httpRequest = new HttpGet(uri); 
      } catch (URISyntaxException e) { 
       System.out.println("Error ::" + e.toString()); 
       e.printStackTrace(); 
      } 

      HttpClient httpclient = new DefaultHttpClient(); 
      HttpResponse response = (HttpResponse) httpclient 
        .execute(httpRequest); 

      HttpEntity entity = response.getEntity(); 
      BufferedHttpEntity bufHttpEntity = new BufferedHttpEntity(entity); 
      InputStream instream = bufHttpEntity.getContent(); 
      Bitmap bm = BitmapFactory.decodeStream(instream); 

      /* 
      * Bitmap bitmap = null; URL imageUrl = new URL(url); 
      * HttpURLConnection conn = (HttpURLConnection) imageUrl 
      * .openConnection(); conn.connect(); conn.getDoOutput(); 
      * 
      * 
      * 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; 
      */ 
      return bm; 
     } catch (Exception ex) { 
      ex.printStackTrace(); 
      return null; 
     } 
    } 

    private Bitmap gonextUrl(String url) { 
     Bitmap bm = null; 
     try { 

      URL imgUrl = new URL(url); 
      HttpGet httpRequest = new HttpGet(imgUrl.toURI()); 

      HttpClient httpclient = new DefaultHttpClient(); 
      HttpResponse response = (HttpResponse) httpclient 
        .execute(httpRequest); 

      HttpEntity entity = response.getEntity(); 
      BufferedHttpEntity bufHttpEntity = new BufferedHttpEntity(entity); 
      InputStream instream = bufHttpEntity.getContent(); 
      bm = BitmapFactory.decodeStream(instream); 

      return bm; 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
     return bm; 
    } 

    // 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. 
      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; 
      } 

      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; 
     } 
    } 

    PhotosQueue photosQueue = new PhotosQueue(); 

    public void stopThread() { 
     photoLoaderThread.interrupt(); 
    } 

    // stores list of photos to download 
    class PhotosQueue { 
     private Stack<PhotoToLoad> photosToLoad = new Stack<PhotoToLoad>(); 

     // removes all instances of this ImageView 
     public void Clean(ImageView image) { 
      for (int j = 0; j < photosToLoad.size();) { 
       if (photosToLoad.get(j).imageView == image) 
        photosToLoad.remove(j); 
       else 
        ++j; 
      } 
     } 
    } 

    class PhotosLoader extends Thread { 
     public void run() { 
      try { 
       while (true) { 

        if (photosQueue.photosToLoad.size() == 0) 
         synchronized (photosQueue.photosToLoad) { 
          photosQueue.photosToLoad.wait(); 
         } 
        if (photosQueue.photosToLoad.size() != 0) { 
         PhotoToLoad photoToLoad; 
         synchronized (photosQueue.photosToLoad) { 
          photoToLoad = photosQueue.photosToLoad.pop(); 
         } 
         Bitmap bmp = getBitmap(photoToLoad.url); 
         memoryCache.put(photoToLoad.url, bmp); 
         String tag = imageViews.get(photoToLoad.imageView); 
         if (tag != null && tag.equals(photoToLoad.url)) { 

          BitmapDisplayer bd = new BitmapDisplayer(bmp, 
            photoToLoad.imageView, indicator); 
          Activity a = (Activity) photoToLoad.imageView 
            .getContext(); 
          a.runOnUiThread(bd); 
         } 
        } 
        if (Thread.interrupted()) 
         break; 
       } 
      } catch (InterruptedException e) { 
       // allow thread to exit 
      } 
     } 
    } 

    PhotosLoader photoLoaderThread = new PhotosLoader(); 

    // Used to display bitmap in the UI thread 
    class BitmapDisplayer implements Runnable { 
     Bitmap bitmap; 
     ImageView imageView; 

     // private ProgressBar indicator1; 

     public BitmapDisplayer(Bitmap b, ImageView i, ProgressBar indicator) { 
      this.bitmap = b; 
      this.imageView = i; 
      // this.indicator1 = indicator; 
     } 

     public void run() { 
      if (bitmap != null) { 
       // indicator1.setVisibility(View.INVISIBLE); 
       imageView.setImageBitmap(bitmap); 
      } else 
       imageView.setImageBitmap(null); 
     } 
    } 

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

} 

Answer 1

調用這個函數loadImageFromUrl（ 「http://www.heresmyparty.com/cms/components/com_chronocontact/uploads/add_event_form/20110805085124_wtpa.logo.png」）從IMAGEURL

public static Bitmap loadImageFromUrl(String url) { 
       InputStream inputStream;Bitmap b; 
       try { 
         inputStream = (InputStream) new URL(url).getContent(); 
         BitmapFactory.Options bpo= new BitmapFactory.Options(); 
         bpo.inSampleSize=2; 
         b=BitmapFactory.decodeStream(new PatchInputStream(inputStream), null,bpo); 
         return b; 
       } catch (IOException e) { 
         throw new RuntimeException(e); 
        } 
//     return null; 
     } 

獲取圖像的位圖這是PatchInputStream

public class PatchInputStream extends FilterInputStream { 
      public PatchInputStream(InputStream in) { 
      super(in); 
      } 
      public long skip(long n) throws IOException { 
      long m = 0L; 
      while (m < n) { 
       long _m = in.skip(n-m); 
       if (_m == 0L) break; 
       m += _m; 
      } 
      return m; 
      } 
     } 

類

您也可以修改您的代碼以防止出現錯誤。只需要在BitmapFactory.decodeStream（新的PatchInputStream（inputStream），null，bpo）中添加PatchInputStream（inputStream）;