Populating a GridView with ImageViews dynamically/programmatically using a ImageAdapter

Question

I try to develop an Android App which allows the user to fetch data from flickr and show it in a GridView (with some nice 3D-Animation). After some adventures i got it almost running, but now I'm stuck.

Here's the problem:

I got a UI Thread "LoadPhotosTask" which gets the pictures from flickr, just like the open source application photostream. In the method onProgressUpdate(LoadedPhoto... value) of that subclass I call addPhoto(). Until now everythings fine - I got some nice Bitmap and Flickr.photo data with all the information I need.

        @Override
    public void onProgressUpdate(LoadedPhoto... value) {

        addPhoto(value);
    }

On the other hand I have got a GridView. Now I want to fill it with the Photos. It has got an adapter called ImageAdapter (which extends BaseAdapter, see this tutorial). If I use an array inside the ImageAdapter class I can populate the GridView with some sample images. But if I want to populate it at runtime, I don't know what to do.

How do I have to set up the getView method in the ImageAdapter? I was trying to fill the array inside the ImageAdapter class with my values in addPhoto, but it doesn't display anything.

So first of all I was setting up the array with the amount of Photos i wanted to display in the grid like that (code is inside the ImageAdapter class):

// class variable
private ImageView[] mThumbIds;

    [...] 

    public void setupArray(int count) {
            this.mThumbIds = new ImageView[count];
        }

Then I call this method with the lenght of my photolist:

    final Flickr.PhotoList list = params[0];
        final int count = list.getCount();
        int helper = 0;
    imagead.setupArray(count);

Afterwards I call the getView method manually inside the addPhoto method:

private void addPhoto(LoadedPhoto... value) {

    ImageView image = (ImageView) mInflater.inflate(
    R.layout.grid_item_photo, null);
    image.setImageBitmap(value[0].mBitmap);
    image.setTag(value[0].mPhoto);

    imagead.setmThumbIds(image, value[0].mPosition);
    imagead.getView(value[0].mPosition, null, mpicturesGrid);

}

That is the getView method inside ImageAdapter:

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

    if (convertView == null) { // if it's not recycled, initialize some
        // attributes

        imageView = new ImageView(mContext);
        imageView.setLayoutParams(new GridView.LayoutParams(EDGE_LENGTH,
        EDGE_LENGTH));
        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setPadding(0, 0, 0, 0);
        imageView.setVisibility(View.VISIBLE);

    } else {

        imageView = (ImageView) convertView;
    }
    imageView.setImageDrawable(mThumbIds[position].getDrawable());
    imageView.setTag(mThumbIds[position].getTag());

    return imageView;

}

General Grievance · Accepted Answer · 2022-11-01 17:42:19Z

9

You are missing a key part.

When you use an Adapter you have a method called notifyDataSetChanged(). The logic you are missing there is the following:

When creating the Adapter for the GridView stay with a reference for the list that the adapter will use. Something like:

private ArrayList<Photo> mPhotos;
private BaseAdapter mAdapter;
private GridView mGridView;

onCreate:

/* other things here */

mAdapter = new MyAdapter(mPhotos);
mGridView.setAdapter(mAdapter);

What you addPhoto should do is the following:

mPhotos.add(photo);
mAdapter.notifyDataSetChanged();

That's it.

edited Nov 1, 2022 at 17:42

General Grievance

5,12039 gold badges40 silver badges60 bronze badges

answered Jan 16, 2011 at 12:42

Macarse

93.3k44 gold badges177 silver badges233 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Julian Vogels Over a year ago

Thanks a lot for your response. I think that's the point.Ok lets see... If I understand correctly, MyAdapter will be my ImageAdapter, won't it? But then, mPhotos will be the context? I apologize, I read through several Adapter tuts, but I still don't get it. How do I have to set up the ImageAdapter/MyAdapter correctly?

Macarse Over a year ago

Yes, MyAdapter == ImageAdapter. Nope, mPhotos is just a list which will hold the photos. For your case, it would be better if you extend ImageAdapter with ArrayAdapter<Photo> in the constructor you can pass it a list of items.

frostymarvelous Over a year ago

Thanks for this. I'm doing the same thing with Gallery. I thought as much that the method would be found in the adapter since nothing is in gallery. SO never fails me. :)

positron Over a year ago

I am fairly new to Android programming, can someone post the whole example - Gallery Activity and the calling Activity? It's a bit hard for me to follow. Thanks.

loicram Over a year ago

Macarse thanks for this answer ! I was using ArrayAdapter before, and I forgot that it's calling that method when add or addAll is called. Now I've implemented my own ImageAdapter and I forgot to add this notification. One more time - Thank you!

Collectives™ on Stack Overflow

Populating a GridView with ImageViews dynamically/programmatically using a ImageAdapter

1 Answer 1

5 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related