自定义ListView行中的Clickable元素

Question

I have created a ListView with custom rows, and within each custom row I would like a particular TextView to be clickable. In the getView method of my custom adapter, I have set an onClickListener to my TextView and implemented onClick(View v) as required. This is where the problem arises.

In onClick(View v), I require the position of the row of the TextView that was clicked in relation to the adapter data (different to the position parameter of getView()). After reading around stack overflow and this article in particular, the magic code required to obtain the position of the row of the TextView that was clicked is:

final int position = listView.getPositionForView(v);

This code works great and everytime I click a TextView for a particular row, the correct position is returned. However, when I rotate the phone to change the configuration and then click any of the TextView's, the position that is returned is always -1. Rotating the phone back to the original configuration also maintains this behaviour of returning -1 when any TextView is pressed.

Looking at the documentation for getPositionForView, it seems -1 is returned (INVALID_POSITION) if the view "does not correspond to a list item (or it is not currently visible)". Why is this happening? Obviously, for me to even be able to click on a TextView the view has to be visible on the screen.

If it matters, I am using convertView and the ViewHolder pattern to optimize the ListView.

What am I missing?

Update: Just to help visualize better, here is what my getView roughly looks like

getView(int position, View convertView, ViewGroup parent) {
        final CustomViewHolder holder;
        View = rowView;
        if (convertView == null) {
            rowView = inflater.inflate(R.layout.listitem, parent, false);
            holder = new CustomViewHolder(rowView);

            holder.textview.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    final int position = listView.getPositionForView(v);
                    //position is always -1 after configuration change
                    Log.d(TAG, "Like button pushed at position: " + position);

                }
            });
            rowView.setTag(postHolder);
        } else {
            rowView = convertView;
            postHolder = (PostListUserPostHolder) convertView.getTag();
        }

        //fill list item with data
    }
    return rowView;
}

UPDATE #2 I seem to have come to a solution. Instead of passing in a reference to the ListView from the fragment to the adapter, I passed in a reference to the fragment itself into the adapter. And then I supplied a getter method in the fragment to obtain the ListView and then used the line:

final int position = fragment.getListView().getPositionForView(v);

I would've thought that this was essentially the same as what I was doing but it seems it is not the case. If anyone could perhaps shed some light on what might be happening it would be appreciated. Otherwise, I am happy that the code is working as expected now!

Answer 1

getView(int position, View convertView, ViewGroup parent) {
        final CustomViewHolder holder;

    if (convertView == null) {
        rowView = inflater.inflate(R.layout.listitem, parent, false);
        holder = new CustomViewHolder();
        convertView .setTag(holder );
    }
    else {

        holder= (CustomViewHolder ) convertView.getTag();
    }

        holder.textview.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                final int position = listView.getPositionForView(v);
                //position is always -1 after configuration change
                Log.d(TAG, "Like button pushed at position: " + position);

            }
        });

    } 

    //fill list item with data
}
return convertView;

}

Answer 2

Your getView() is a bit strange. The field textview of your holder is never initialized ?

The usefulness of the holder is to limit the use of the method findViewById .

Here is the skeleton that I would have used :

static class ViewHolder {
  public TextView textview;
}

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

   // reuse views
  if (rowView == null) {
       LayoutInflater inflater = context.getLayoutInflater();
       rowView = inflater.inflate(R.layout.listitem, null);
       // configure view holder
       ViewHolder viewHolder = new ViewHolder();
       viewHolder.textview= (TextView) rowView.findViewById(R.id.textview);
       rowView.setTag(viewHolder);
  }
  else {

      ViewHolder holder = (ViewHolder) rowView.getTag();
  }

   // fill data
   holder.textview.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            final int position = listView.getPositionForView(v);
            //position is always -1 after configuration change
            Log.d(TAG, "Like button pushed at position: " + position);

        }
    });

    return rowView;
 }
} 

Hopefully it solve your problem !

have a nice day !