TextView value changes back to previous value after scroll in base adapter

Question

I\'ve been researching this forever and can\'t find a solution. Everything about my custom list view seems to perform correctly. When I click on the holder.feedUpVoteButto

Answer 1

Every single time getView is called, you re-make

likes = new int[GlobalFeedTab.arrayFeedList.size()];

This is not saved as you scroll and the row you clicked leaves and re-enters the display. The holder could hold this integer value.

private class ViewHolder {
    int likes;
    TextView feedNumOfLikes; 
}

And update it accordingly

holder.feedUpVoteButton
    .setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            holder.feedNumOfLikes.setText(String.valueOf(++holder.likes));

However, you need to also update the parse object.

parseObFeed.put("likes", holder.likes);
parseObFeed.saveInBackground();
// notifyDataSetChanged(); // Up to you. Might not work without

I refuse to use notifyDatasetChanged because I am not adding anything or removing anything from the list.

You are modifying the data, though. Calling it will make your adapter data consistent with what is stored in your Parse Server.

---

Edit

This gets complicated because you are making each "row" have some "nested" list of objects that are associated with it. I suppose you could store that entire list in the holder.

private class ViewHolder {
    // Java variables to hold onto
    int likes;
    List feedItems = new ArrayList();

    // Android views to bind those values to
    TextView feedNumOfLikes; 
}

When inside the adapter, you call Parse to get this secondary list for each item in your adapter, but you only need to store that within the holder. Don't do anything else with it when the query2 returns .

Your real issue here is that is unclear what query2 is even returning. It's some list of data, sure, but are you actually wanting to display a List within a List? Also, each item of the adapter is querying the exact same data from Parse. I think you need a filter... Then, your position variable doesn't correspond between GlobalFeedTab.arrayFeedList and the List, because those are different lists.

Here's just some comments that I can point out.

    else {
        holder = (ViewHolder) view.getTag();
    }

    // You don't need 'position', it is just the 'i' value...
    mFeed = GlobalFeedTab.arrayFeedList.get(i);

    // This is stored in the Activity, I guess? 
    likesString = mFeed.get("likes");
    holder.feedNumOfLikes.setText(likesString);

    holder.feedUpVoteButton.setTag(i);

    ParseQuery query2 = new ParseQuery("FeedItem");

    // This is getting some related "FeedItem" for the current row
    // Just store the info, don't do anything with it yet
    query2.findInBackground(new FindCallback() {
        @Override
        public void done(final List objects, ParseException e) {
            if (e == null) {
                holder.feedItems.clear();
                holder.feedItems.addAll(objects);
                notifyDataSetChanged();
            }
        } 
    };

    // Here, you can setup the button for the current row
    holder.feedUpVoteButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            int pos = (Integer) v.getTag();

            // This is wrong... 'pos' is the position of the adapter! Not the index of List results from earlier
            // And this is a very clear ArrayIndexOutOfBounds error...
            // The adapter could be shorter/longer than the holder.feedItems
            parseObFeed = holder.feedItems.get(pos);

            // !! TODO: Figure out which parseObFeed you actually want to use here 

            username = parseObFeed.getString("username");
            createdAt = parseObFeed.getDate("createdAt");

            holder.likes++;
            parseObFeed.put("likes", holder.likes);

            // This is the value that "resets" when you scroll. 
            // parseObFeed has not yet been saved, so when you scroll, the data isn't changed. 
            holder.feedNumOfLikes
                 .setText(String.valueOf(parseObFeed.getInt("likes")));

            // Not really sure what this does - You can store an array of likes rather than one field per username
            parseObFeed.put(ParseUser.getCurrentUser().getUsername() + "upvoteClicked", true);

            parseObFeed.saveInBackground();
            notifyDataSetChanged();
        }
    });    
}

I can't remember if saveInBackground has a callback, but that might be something to look into