Can Universal image loader for android work with i

问题:

I would like to store my images in an sqlite db, in blob-s, and maybe encrypt them. Is it possible to use the Android-Universal-Image-Loader with images from an sqlite database?

回答1:

UIL doesn't support of images from SQLite DB out of the box. But you can add this support yourself, you just need come up with new scheme/protocol name (e.g. db://), implement own ImageDownloader and set it to configuration.

For example:

Lets choose own scheme db so our URIs will look like "db://...".

Then implement ImageDownloader. We should catch URIs with our scheme, parse it, find needed data in DB and create InputStream for it (it can be ByteArrayInputStream).

public class SqliteImageDownloader extends BaseImageDownloader {

    private static final String SCHEME_DB = "db";
    private static final String DB_URI_PREFIX = SCHEME_DB + "://";

    public SqliteImageDownloader(Context context) {
        super(context);
    }

    @Override
    protected InputStream getStreamFromOtherSource(String imageUri, Object extra) throws IOException {
        if (imageUri.startsWith(DB_URI_PREFIX)) {
            String path = imageUri.substring(DB_URI_PREFIX.length());

            // Your logic to retreive needed data from DB
            byte[] imageData = ...;

            return new ByteArrayInputStream(imageData);
        } else {
            return super.getStreamFromOtherSource(imageUri, extra);
        }
    }
}

Then we set this ImageLoader to configuration:

ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(context)
        ...
        .imageDownloader(new SqliteImageDownloader(context))
        .build();

ImageLoader.getInstance().init(config);

And then we can do following to display image from DB:

imageLoader.displayImage("db://mytable/13", imageView);