从 AndroidHttpClient 迁移到 URLConnection

Question

我对此比较陌生，我一直在使用 AndroidHttpClient 来帮助通过 Parse 将图像下载到我的应用程序。现在使用 Sdk 23，我必须重写一些类。我的问题很简单。

我们以下面的代码为例，它没有做任何事情：

new TwinPrimeSDK(getApplicationContext(), "12345678-1234-1234-1234-123456789012-1234567-123");
    try {
        URLConnection httpConn = TPURLConnection.openConnection("your-URL");
    } catch (IOException e) {
        e.printStackTrace();
    }

"your-URL" 指的是什么？使用基于 Apache 的 AndroidHttpClient，我从来不需要为任何事情使用特定的 URL。它刚刚起作用。

更新：

public class ImageLoader {

    // Last argument true for LRU ordering
    private Map<String, String> objectIdToUriMap = Collections.synchronizedMap(new LinkedHashMap<String, String>(10, 1.5f, true));

    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(FileCache fileCache) {
        //fileCache = new FileCache(context);
        this.fileCache = fileCache;
        executorService = Executors.newFixedThreadPool(5);

        // need to re-evaluate where to do this as it is causing problems with not being able to download feed items as they are cleared from cache
        //clearCache();
        // only clear file cache, we're not using mem cache (every time we instantiate with a filecache)
        fileCache.clear();
    }


    public void DisplayImage(String url, ImageView imageView, ProgressBar progress) {
        imageViews.put(imageView, url);
        Bitmap bitmap = memoryCache.get(url);
        if (bitmap != null) {
            imageView.setImageBitmap(bitmap);
        }
        else {
            queuePhoto(url, imageView, progress);
            //imageView.setImageResource(stub_id);
            imageView.setVisibility(View.GONE);

            if(progress != null) {
                progress.setVisibility(View.VISIBLE);
            }
        }
    }

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

    // must be run in a thread
    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);
            FeedUtils.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;
        }
    }

    public Uri getImageURIWithDownload(String url) {
        // try getting file from cache 1st
        File f = fileCache.getFile(url);
        if (f != null) {
            if(f.exists()) {
                return Uri.fromFile(f);
            }
        }

        // get bitmap from http (or cache, in fact)
        getBitmap(url);

        // try getting file again
        f = fileCache.getFile(url);
        return (f != null) ? Uri.fromFile(f) : null;
    }

    // Decodes image and scales it to reduce memory consumption
    // note. wda. doesn't use sample size (no scaling!)
    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.
            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 ProgressBar progress;

        public PhotoToLoad(String u, ImageView i, ProgressBar p) {
            url = u;
            imageView = i;
            progress = p;
        }
    }

    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);
                photoToLoad.imageView.setVisibility(View.VISIBLE);
                if(photoToLoad.progress != null)
                    photoToLoad.progress.setVisibility(View.GONE);
            }
            else {}
                //photoToLoad.imageView.setImageResource(stub_id);
        }
    }

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

}

Answer 1

What does the "your-URL" refer to?

它指的是您要从中访问信息的url。

With AndroidHttpClient over Apache I never had to use a specific URL for anything. It just worked.

不，在这种情况下，您也需要提供 url。

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

如果你想使用http请求，它应该有一个请求url，没有它不知道从哪里获取数据。

从 AndroidHttpClient 迁移到 URLConnection

Migrating from AndroidHttpClient to URLConnection

java

android

urlconnection

parse-platform

androidhttpclient