如何在不下载的情况下显示来自 GridView 中 URL 的图像？

Question

Problem is that the whole process for above is very slow first, With AsyncTask class (DownloadTask), websource is downloaded. Second, images' URL are downloaded and added in ArrayList (URLsList). Third, For each URL in Arraylist images is downloaded (using ImageDownloadTask). Fourth, each image is added to ArrayList (ImagesList). Fifth, with baseadapter images are shown in gridView. This whole process is very slow. How it can be made fast? OR how to directly pass images to Gridview without downloading it. Below is the code.

private void GetImageList() {
// This method download image from URL Using AsyncTask
        ImageDownloadTask ImageTask;
        Bitmap Image;
        int i = 0;

        try {
            while (i < URLsList.size()) {

                ImageTask = new ImageDownloadTask();
                Image = ImageTask.execute(URLsList.get(i)).get();
                ImagesList.add(Image);
                i = i + 1;
                //Log.i("Images:" ,i + " Added");

            }

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

    }


    public void GetAllURLs() {
// This method download webSource and fetch URLs Using AsyncTask
        DownloadTask task = new DownloadTask();
        String linkToImageUrlSource = null;
        try {
            //showDialog(progress_bar_type);

            linkToImageUrlSource = task.execute("https://posh.in/kandasar").get();
            Pattern p = Pattern.compile("<a href=\"(.*?)\" class=\"image-container\"");
            Matcher m = p.matcher(linkToImageUrlSource);

            while (m.find()) {
                DownloadTask task2 = new DownloadTask();
                String imageUrlSource = null;
                try {
                    imageUrlSource = task2.execute(m.group(1)).get();
                    Pattern p1 = Pattern.compile("class=\"image-viewer-main image-viewer-container\"><img src=\"(.*?)\"");
                    Matcher m1 = p1.matcher(imageUrlSource);
                    while (m1.find()) {
                        //Log.i("URL: ", m1.group(1));
                        AdURLsList.add(m1.group(1));
                    }

                    p1 = Pattern.compile("alt=\"(.*?)\" width");
                    m1 = p1.matcher(imageUrlSource);
                    while (m1.find()) {
                        //Log.i("DESC: ", m1.group(1));
                        AdImagesDescList.add(m1.group(1));
                    }

                } catch (Exception e2) {
                    e2.printStackTrace();
                }
            }

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

    }



// BaseAdpater

    public class ImageAdapater extends BaseAdapter {
        @Override
        public int getCount() {
            return AdImagesList.size();
        }

        @Override
        public Object getItem(int i) {
            return AdImagesList.get(i);
        }

        @Override
        public long getItemId(int i) {
            return 0;
        }

        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {
            View galleryView = null;

            if (galleryView == null) {
                galleryView = getLayoutInflater().inflate(R.layout.layout_for_gridview, viewGroup, false);
                ImageView sampleImage = (ImageView) galleryView.findViewById(R.id.adImage);
                sampleImage.setImageBitmap(AdImagesList.get(i));
            }

            return galleryView;
        }
    }



    class DownloadTask extends AsyncTask<String, Void, String> implements com.example.urlapplication.DownloadTask {


        @Override
        protected String doInBackground(String... urls) {
            String result = "";
            URL url;
            HttpURLConnection urlConnection = null;

            try {
                url = new URL(urls[0]);
                urlConnection = (HttpURLConnection) url.openConnection();
                InputStream in = urlConnection.getInputStream();
                InputStreamReader reader = new InputStreamReader(in);
                int data = reader.read();
                while (data != -1) {
                    char current = (char) data;
                    result = result + current;
                    data = reader.read();
                }
                return result;
            } catch (Exception e) {
                e.printStackTrace();
                return "FAILED";
            }

        }

    }

    class ImageDownloadTask extends AsyncTask<String, Void, Bitmap> {

        @Override
        protected Bitmap doInBackground(String... urls) {
            try {
                URL url = new URL(urls[0]);
                HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                connection.connect();
                InputStream inputStream = connection.getInputStream();
                Bitmap adBitmap = BitmapFactory.decodeStream(inputStream);
                return adBitmap;
            } catch (Exception e) {
                e.printStackTrace();
                return null;
            }
        }

    }

How can I show images in gridview without downloading it.

Answer 1

Use Picasso/Glide to load image url into image View

val placeImage= itemView.findViewById<ImageView>(R.id.place_image)
Picasso.with(context).load(Uri.parse(data.url)).into(placeImage)

Check this link: https://github.com/Krishnasony/TestApp