Question

Hi all,
I have searched a lot for my problem, I found a lot of posts with similar problems, but no one gave me a correct solution.
What I want is a gridview displaying a sdcard folder’s images. I also have to offer the possibility to take a picture, and when going back to the gridview, update it with the new picture.

To take the picture, I use this code :

Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
intent.putExtra(MediaStore.EXTRA_OUTPUT, getImageFileUri());
startActivityForResult(intent, TAKE_PICTURE_ACTIVITY);

Where getImageFileUri() is a function giving me a picture name with a timestamp, using Environment.getExternalStorageDirectory() to get the sdcard path, and checking if the folder exists (and create it if it doesn’t).

For the moment, I use a cursor to get my images :

private void displayGallery() {

    // Query params :
    Uri uri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
    String[] projection = {MediaStore.Images.Media._ID};
    String selection = MediaStore.Images.Media.DATA + " like ? ";
    String[] selectionArgs = {"%Otiama%"};

    // Submit the query :
    mCursor = managedQuery(uri, projection, selection, selectionArgs, null);

    if (mCursor != null) {

        mGridView.setOnItemClickListener(this);
        mGridView.setAdapter(new ImageAdapter(this, mCursor));
    }

    else showToast("Gallery is empty : " + uri.toString());
}

And here is my adapter’s getView :

public View getView(int position, View convertView, ViewGroup parent) {

    ImageView imageView = new ImageView(mContext);

    // Move cursor to current position
    mCursor.moveToPosition(position);

    // Get the current value for the requested column
    int columnIndex = mCursor.getColumnIndexOrThrow(MediaStore.Images.Media._ID);
    int imageID = mCursor.getInt(columnIndex);

    // obtain the image URI
    Uri uri = Uri.withAppendedPath( MediaStore.Images.Media.EXTERNAL_CONTENT_URI, Integer.toString(imageID) );
    String url = uri.toString();

    // Set the content of the image based on the image URI
    int originalImageId = Integer.parseInt(url.substring(url.lastIndexOf("/") + 1, url.length()));
    Bitmap b = MediaStore.Images.Thumbnails.getThumbnail(mContext.getContentResolver(), originalImageId, MediaStore.Images.Thumbnails.MINI_KIND, null);
    imageView.setImageBitmap(b);

    return imageView;
}

This code works, but is very slow and doesn’t update (new pictures’s thumbnails aren’t created), even if I call again my displayGallery() function in the onActivityResult(). Well, it doesn’t update even if I reload the app >< . I have to run it again from eclipse.

In fact, what I would like is the same behavior than ES File Explorer (when you open a folder, the pictures have all a preview image, and they are loaded asynchronously), which, I think, doesn’t use those ** thumbnails.

So I tried to load the pictures as bitmaps using the bitmap factory, but even with a few pictures (1-2), I instantly get a “java.lang.OutOfMemoryError: bitmap size exceeds VM budget”… I guess I have to resize them, but if I do so, won’t I have the same error when I will load 20-30 pictures ?? Or the problem is that each picture exceeds the budget, and so if I resize them I will avoid this error for all of them ?

Sorry for the big post, if someone can help…

Answer 1

Well, I answer myself :
I created my own thumbnails this way :

public static Bitmap resizedBitmap(Bitmap bitmap, int newWidth) {

    // Get the bitmap size :
    int width = bitmap.getWidth();
    int height = bitmap.getHeight();
    double ratio = (double)width / (double)height;

    // Compute the thumbnail size :
    int thumbnailHeight = newWidth;
    int thumbnailWidth = (int) ( (double)thumbnailHeight * ratio);

    // Create a scaled bitmap :
    Bitmap scaledBitmap = Bitmap.createScaledBitmap(bitmap, thumbnailWidth, thumbnailHeight, false);

    return scaledBitmap;
}

I don’t use cursors anymore, to load the thumbnails I proceed like this (in the ImageAdapter) :

public void loadThumbnails() {

    // Init the ArrayList :
    _thumbnails = new ArrayList<ImageView>();
    _imagesNames = new ArrayList<String>();

    // Run through the thumbnails dir :
    File imagesThumbnailsDir = new File(_imagesThumbnailsDirUri.getPath());
    File[] imagesThumbnails = imagesThumbnailsDir.listFiles();
    Arrays.sort(imagesThumbnails);

    // For each thumbnail :
    for(File imageThumbnail : imagesThumbnails)
    {
        // Check if the image exists :
        File image = new File(_imagesDirUri.getPath() + File.separator + imageThumbnail.getName());
        if(image.exists()) {

            ImageView imageView = new ImageView(_context);
            imageView.setImageDrawable(Drawable.createFromPath(imageThumbnail.getAbsolutePath()));

            _thumbnails.add(imageView);
            _imagesNames.add(imageThumbnail.getName());
        }

        // If not, delete the thumbnail :
        else {

            ImageUtils.deleteFile(Uri.fromFile(imageThumbnail));
        }
    }
}

And so my ImageAdapter’s getView function sounds like this :

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    ImageView imageView;
    if (convertView == null) {

        imageView = new ImageView(_context);
        imageView.setLayoutParams(new GridView.LayoutParams(80, 80));
        imageView.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
        imageView.setPadding(5, 5, 5, 5);

    } else {
        imageView = (ImageView) convertView;
    }

    imageView.setImageDrawable(_thumbnails.get(position).getDrawable());

    return imageView;
}

Hope it helps..