CODEWITHSUNDEEP
androidlistviewposition
Vlad Alexeev
Vlad Alexeev

Reputation: 2204

Wrong position number in a ListView

I got this problem several times and even though I can't solve it

here's code from Adapter

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


        if(convertView == null){
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.place_item_layout, parent, false);
            //HERE's my check
            (convertView.findViewById(R.id.divdePlaces)).setVisibility(View.GONE);
            if (place.isTOP()==false && position!=0) if (places.get(position-1).isTOP()==true) {
                //turn back on
                (convertView.findViewById(R.id.divdePlaces)).setVisibility(View.VISIBLE);   
            }

.. etc..

}
return convertView;
}

So, this just turn on the divider line if conditions are met. I thought here the position should be the real number but it repeats again when ListView goes 1 screen up, even though the conditions for it are not met for sure.

How do I fix that?

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Upvotes: 0

Views: 43

Answers (2)

matiash
matiash

Reputation: 55340

This problem is derived from view reuse in ListView. As you scroll down, the item views that exit from the top are reused (supplied as convertView) for the new items. Therefore, you need to make sure that you "undo customizations" if they no longer apply.

For example:

if (convertView == null)
{
     // create new view.
     convertView = inflater.inflate(...);
}

// OUTSIDE the previous if, and with both branches implemented.
if (check)
     (convertView.findViewById(R.id.divdePlaces)).setVisibility(View.VISIBLE);   
else
     (convertView.findViewById(R.id.divdePlaces)).setVisibility(View.GONE);   

...

Upvotes: 1

selbie
selbie

Reputation: 104514

As you scroll one page up, your views start to get recycled. Hence, convertView is already inflated and non-null. Toggle the visibility of the divider outside of the if (convertView==null) block.

Something like this:

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


    if(convertView == null)
    {
        LayoutInflater inflater = (LayoutInflater) context.getSystemService Context.LAYOUT_INFLATER_SERVICE);

        convertView = inflater.inflate(R.layout.place_item_layout, parent, false);
    }

    int visibility = (place.isTOP()==false && position!=0) ? View.GONE : View.VISIBLE;
    convertView.findViewById(R.id.divdePlaces).setVisibility(visibility);

    return convertView;

}

Upvotes: 1

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