在ListView中滚动时保留“图像”按钮的图像

Question

I'm having a problem while implementing a "mark as favorite" function in my listview. I have an ImageButton placed on the right side of every listview item and "on click" I want to change the image of the button. It should look like this:

That's pretty easy to implement and works perfectly fine. The problem now is when I scroll the list, the selected image buttons (stars) won't stay the same.

To keep the selection of a listview item isn't that hard, but to keep the changed image in the list is an issue for me. The former can be implemented in this way: https://stackoverflow.com/a/9281155/2054118

So I tried something similar. In the getView() method I init my imagebutton and its OnClickListener to save the actual position in a LinkedList. All positions of the selected ImageButtons should be in the list:

MyAdapter.java:

private LinkedList<Integer> selectedIndeces;

...

private static class ViewHolder {
    ...
    public ImageButton favoriteButton;
}

public void changeSelectedPositions(int pos) {
    int index = this.selectedIndeces.indexOf(pos);
    if (index != -1) {
        // image button in this row was selected
        this.selectedIndeces.remove(index);
    } else {
        // mark position of the image button as selected
        this.selectedIndeces.add(pos);
    }
    notifyDataSetChanged();
}

...

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

    View rowView = convertView;

    // reuse views
    if (rowView == null) {
        rowView = this.mInflater.inflate(R.layout.talk_list_child, null);
        // configure view holder
        ViewHolder viewHolder = new ViewHolder();

        ...

        ImageButton ib = (ImageButton) rowView.findViewById(R.id.ib_favorite);
        ib.setFocusable(false);
        ib.setFocusableInTouchMode(false);
        ib.setOnClickListener(new OnClickListener() {
            public void onClick(View button) {
                // Set the button's appearance
                button.setSelected(!button.isSelected());
                changeSelectedPositions(position);
            }
        });
        viewHolder.favoriteButton = ib;
    }

    // fill data
    ViewHolder holder = (ViewHolder) rowView.getTag();

    ...

    if (selectedIndeces.contains(position)) {
        holder.favoriteButton.setImageResource(R.drawable.fav_selected);
    } else {
        holder.favoriteButton.setImageResource(R.drawable.fav_unselected);
    }

}

But the problem is that the position I get in getView() isn't always the same and depends on where the list is scrolled to?

So to shorten my question: How can I keep the selection/image of my ImageButtons in the ListView even when I scroll?

Answer 1

You saved your position while preparing viewHolder . Then after scrolling, view is recycled and the same viewHolder with previously stored position is used. You can just set listener every time you get getView() call.

Move

ib.setOnClickListener(new OnClickListener() {
    public void onClick(View button) {
        // Set the button's appearance
        button.setSelected(!button.isSelected());
        changeSelectedPositions(position);
    }
});

Just before

if (selectedIndeces.contains(position)) {

Answer 2

1. Keep an array list to save the position which is clicked in your adapter

   iconClickedPostion = new ArrayList();

2. Whenever you handle your click for the image button in the list, add the position of the listview in the arraylist.

   iconClickedPostion.add(position);

3. In getView(), check the condition if it is already clicked then set the desired image.

   if(iconClickedPostion.contains(position)){ completedIcon.setImageResource(R.drawable.ic_done); } else { completedIcon.setImageResource(iconId[position]); }