Load Image in ImageView from URL stored in JSONString in Android

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梦如初夏
梦如初夏 2021-01-13 13:31

I have a JSON string, say a name and a Url . I need to extract name into the TextView and extract and display image in ImageView. Belo

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  • 2021-01-13 13:58

    Use Universal Image Loader to load image very fast and smooth

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  • 2021-01-13 14:10

    You can use GSON library to parse the json into a plain Java Object and then use that object to fill in the TextView and ImageView. If you don't want to use external libraries you can use JSON classes like this:

    JSONObject object = new JSONObject("your strnig");
    JSONObject webimages = object.getJSONObject("WebImages");
    String imageName = webimages.getString("image_name")
    String imageUrl = webimages.getString("imageurl")
    
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  • 2021-01-13 14:13

    You can do something like this.

             public static final String JSON_STRING="{"WebImages":{"Imagename":"image_name","imageurl":http://www.example.com/image/example.png}}";
        private ImageLoader _ImageLoader;
    
                        try {
                JSONObject _jObj = new JSONObject(JSON_STRING);
                JSONObject _jSubObj = _jObj .getJSONObject("WebImages");
            String _imageName= _jSubObj.getString("Imagename");
    YOUR_TEXTVIEW.setText(_imageName);
            String _imageURL= _jSubObj.getString("imageurl");
          _ImageLoader = new ImageLoader(CURRENT_ACTIVITY.this);
           _ImageLoader.DisplayImage(_imageURL,
                            R.drawable.ic_launcher, YOUR_IMAGEVIEW);
                    } catch (JSONException e) {
                                            // TODO Auto-generated catch block
    
                                            e.printStackTrace();
                                        }
    
    
        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)
            {
                try {
    
                    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);
    
    
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
    
            private void queuePhoto(String url, ImageView imageView)
            {
                PhotoToLoad p=new PhotoToLoad(url, imageView);
                executorService.submit(new PhotosLoader(p));
            }
    
            public 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;
                }
    
            }
    
            public Bitmap getFacebookImage(String userId) {
                // TODO Auto-generated method stub
                Bitmap bitmap = null;
    
                try {
    
                HttpGet httpRequest = new HttpGet(
                URI.create(userId));
                HttpClient httpclient = new DefaultHttpClient();
                HttpResponse response = (HttpResponse) httpclient
                .execute(httpRequest);
                HttpEntity entity = response.getEntity();
                BufferedHttpEntity bufHttpEntity = new BufferedHttpEntity(
                entity);
                bitmap = BitmapFactory
                .decodeStream(bufHttpEntity
                .getContent());
                httpRequest.abort();
    
                } catch (Exception e) {
                e.printStackTrace();
                }
                return bitmap;
                }
    
            //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=200;
                //  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=1;
                    return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
    
                } catch (FileNotFoundException e) {
    
                }catch (Exception 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() {
                    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();
            }
    
        }
    
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  • 2021-01-13 14:19

    You could extract the image name and url like this

     public static final String JSON_STRING="{\"WebImages\":{\"Imagename\":\"image_name\",\"imageurl\":http://www.example.com/image/example.png}}"; 
    JSONObject jsonObject = new JSONObject(JSON_STRING);
    JSONObject webImages = jsonObject.getJSONObject("WebImages");
    String imageName = webImages.getString("Imagename");
    String imageUrl = webImages.getString("imageurl");
    

    Now, you have the imageName and the imageUrl. You can easily set the text doing something like myTextView.setText(imageName). For loading the image into ImageView, I suggest using the Picasso library. It is extremely easy to use. All you need is one line of code, which would look like

    Picasso.with(context).load(imageUrl).into(imageView);
    
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  • 2021-01-13 14:21

    First of all use Gson to parse Json and get url as a String, then you can use UniversalImageLoader library (it does the async image download and very easy to use) https://github.com/nostra13/Android-Universal-Image-Loader

    static public DisplayImageOptions options= new DisplayImageOptions.Builder().cacheOnDisk(true).cacheInMemory(true).build();
        imageLoader.displayImage(imgUrl, ivImage, options, new ImageLoadingListener() {
    
            public void onLoadingStarted(String imageUri, View view) {
                ((ImageView)view).setImageResource(R.drawable.nofoto);
            }
    
            public void onLoadingFailed(String imageUri, View view, FailReason failReason) {
                ((ImageView)view).setImageResource(R.drawable.nofoto);
            }
    
            public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
    
            }
    
            public void onLoadingCancelled(String imageUri, View view) {
            }
    
        });
    
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