CODEWITHSUNDEEP
androidandroid-listview
Junaid
Junaid

Reputation: 7860

Erratic behaviour of listview (Android)

In my listview I have a custom Adapter, which I build using a TreeMap, I defined the getView method which is as follows. I am trying to strike out the text in a certian textview of the listview on click, only those textviews will be striken off which contain a certain pattern of characters (y@y). However on clicking one row in the listview I am getting strike out effect on some other row. 

    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);



        if (convertView == null) { 
            convertView = inflater.inflate(R.layout.chklistlayout, parent, false); 
        }
        TextView textView = ((TextView) convertView.findViewById(R.id.textView1));
        TextView imageview = ((TextView) convertView.findViewById(R.id.textView2));
        textView.setText(values[position]);
        imageview.setText(mValues[position]);


        String s = mValues[position];
        if (s.contains("y@y")) {
            System.out.println("In if of getview");
            System.out.println(s);
            imageview.setPaintFlags(imageview.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
        } else {

        }

        return convertView;
    }
}

I tried using a holder pattern too, using a static holder class, but the problem seems to persist. Any pointers?

Upvotes: 1

Views: 145

Answers (1)

Budius
Budius

Reputation: 39836

this answer is half mine and half from Muhammad Babar that we both commented on the question making together a quite nice answer:

use else block to handle this, imageview.setPaintFlags() not to strike

that happens

Because of the convertView. When you scroll the list the same view that was used before is give back to getView method. So the same imageView that you painted with StrikeThrough before is still painted with it. So you have to revert that action.

more over, because of this recycling, usually dealing with Adapters you must ALWAYS undo/revert/repaint/change text/change image to all the elements to make sure it will be on screen the way you want.

ps.: now you should apply a Holder pattern to get better performance.

Upvotes: 2

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