Question

I would like to load images into a gallery view from a url?

I first make them a bitmap using this.

URL aURL = new URL(myRemoteImages[position]);
URLConnection conn = aURL.openConnection();
conn.setUseCaches(true);
conn.connect();
Object response = conn.getContent();
if (response instanceof Bitmap) {
    Bitmap bm = (Bitmap)response;

    InputStream is = conn.getInputStream();  
    /* Buffered is always good for a performance plus. */
    BufferedInputStream bis = new BufferedInputStream(is);
    /* Decode url-data to a bitmap. */

    bm = BitmapFactory.decodeStream(bis);
    bis.close();
    is.close();
    Log.v(imageUrl, "Retrieving image");

    /* Apply the Bitmap to the ImageView that will be returned. */
    i.setImageBitmap(bm);

How could I go about caching this bitmap? So when the user swipes the screen it doesn’t reload over and over?

EDIT: I CALL getImage() to retreive the text url for each url.

i use both of these in a asyncTask. preExecute i call getImage()
and doInBackground i set the gallery to the imageAdapter.

    private class MyTask extends AsyncTask<Void, Void, Void>{


                @Override
                protected Void doInBackground(Void... arg0) {try {
                            getImages();
                            Log.v("MyTask", "Image 1 retreived");
                            getImage2();
                            Log.v("MyTask", "Image 2 retreived");
                            getImage3();
                            Log.v("MyTask", "Image 3 retreived");
                            getImage4();
                            Log.v("MyTask", "Image 4 retreived");
                        } catch (IOException e) {
                            Log.e("MainMenu retreive image", "Image Retreival failed");
                            e.printStackTrace();
                        }
                    return null;
                }
                @Override

                protected void onPostExecute(Void notUsed){
                    ((Gallery) findViewById(R.id.gallery))
                          .setAdapter(new ImageAdapter(MainMenu.this));


                }

                        }

EDIT: getView() method

    public View getView(int position, View convertView, ViewGroup parent) {
                ImageView i = new ImageView(this.myContext);

                try {

                                URL aURL = new URL(myRemoteImages[position]);
                                URLConnection conn = aURL.openConnection();
                                conn.setUseCaches(true);
                                conn.connect();
                                Object response = conn.getContent();
                                if (response instanceof Bitmap) {
                                  Bitmap bm = (Bitmap)response;

Answer 1

You could store your images on the SDCard and on the launch of your application you need to initialize a component that keeps a HashMap<String,Bitmap> and initialize the map with the contents of a folder from the SDCard.

When you will need an image, you will first check if your HashMap contains the key of that image, let say myMap.contains(myFileName) and if it does you will fetch the image from the map, and if the image is not contained in your map you will need to download it, store id on the SDCard and put in in your map.

I’m not sure if this is the best solution, since if you have a large number of Bitmaps your application can run out of resources. Also I think storing Drawable instead of Bitmap will be less memory consuming.

EDIT:For your problem you need create a custom class that has a member Drawable and execute the URLConnection just when you first create your objects. After that in the getView() method you will just use myObj.getMyDrawable() to access the drawable for that specific object.