Question

我的代码中有https://www.dropbox.com/s/ri4xbjaz64kezsg/30.jpg这个链接...但我无法从该链接下载图像..如果我使用链接其他然后此链接，那么我可以下载。所以这个链接有什么问题......请帮助我

public class AndroidLoadImageFromURLActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    // Loader image - will be shown before loading image
    int loader = R.drawable.loader;

    // Imageview to show
    ImageView image = (ImageView) findViewById(R.id.image);

    // Image url
    String image_url = "https://www.dropbox.com/s/ri4xbjaz64kezsg/30.jpg";

    // ImageLoader class instance
    ImageLoader imgLoader = new ImageLoader(getApplicationContext());

    // whenever you want to load an image from url
    // call DisplayImage function
    // url - image url to load
    // loader - loader image, will be displayed before getting image
    // image - ImageView 
    imgLoader.DisplayImage(image_url, loader, image);
}

}

这是图像加载器类.....................

public class ImageLoader {

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

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

int stub_id = R.drawable.ic_launcher;
public void DisplayImage(String url, int loader, ImageView imageView)
{
    stub_id = loader;
    imageViews.put(imageView, url);
    Bitmap bitmap=memoryCache.get(url);
    if(bitmap!=null)
        imageView.setImageBitmap(bitmap);
    else
    {
        queuePhoto(url, imageView);
        imageView.setImageResource(loader);
    }
}

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.
        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;
        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;
    }

    @Override
    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();
}

}

Answer 1

当您下载此链接的内容时，您实际上正在下载http网页而不是图像本身。然后，此Dropbox网页会显示图像，以便您可以在浏览器中看到它，但ImageLoader需要直接链接到图像。

直接链接到图片

https://dl.dropboxusercontent.com/s/ri4xbjaz64kezsg/30.jpg

如果在www.dropbox的网址中缺少www，则可以替换dropbox或dl.dropboxusercontent。简单示例帮助方法：

public static String modifyDropboxUrl(String originalUrl)
{
    String newUrl = originalUrl.replace("www.dropbox." ,"dl.dropboxusercontent.");

    //just for sure for case if www is missing in url string
    newUrl = newUrl.replace("dropbox.", "dl.dropboxusercontent.");

    return newUrl;
}

Answer 2

在我看来，问题的原因是ImageLoader类不支持SSL，而dropbox强制其客户端使用它。尝试使用另一个类（具有SSL支持）来完成此任务，可能是：https://github.com/nostra13/Android-Universal-Image-Loader/issues/188#issuecomment-14311274。

Answer 3

为什么不使用库作为通用图像加载器或AQuery！这节省了你这么多时间！使用它而不是无数的代码行

AQuery aq = new Aquery(Activity.this);
 aq.id(R.id.imageview).image(url, true, true);

我在使用aquery之前还处理缓存！非常非常轻松

从网址加载图片无法正常工作

3 个答案: