Question

I am currently working on a ListView that contains around 80 to 100 items (TextViews). I don’t think it is too much content, but when i scroll (with fingers) the ListView is bobbing or laging. However, when I use the “fast-scroll-button” – that thing on the right of the ListView – the scrolling appears very consistent and smooth.

Did anyone have the same problem? I tested the ListView on my HTC Sensation.

Here is my ListView code:

<ListView
     android:id="@+id/list_view"
     android:layout_height="match_parent"
     android:layout_width="match_parent"
     android:scrollingCache="true">

</ListView>

And the Java code:

adptr = new ArrayAdapter<String>(iF, R.layout.list_item, showing) {

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

            LinearLayout lin = new LinearLayout(this.getContext());
            lin.setOrientation(LinearLayout.HORIZONTAL);

            // Icon
            ImageView v = new ImageView(this.getContext());
            // v.setBackgroundDrawable(iF.getResources().getDrawable(R.drawable.cube_icon));

            // Text
            TextView txt = new TextView(this.getContext());
            txt.setTextSize(Float.valueOf(prefs.getString("pref_txtSize", "12")));
            txt.setPadding(10, 10, 10, 10);
            txt.setText(this.getItem(position));
            txt.setTextColor(getLineColor(position));

            // Shortcut
            LinearLayout shortLin = new LinearLayout(this.getContext());
            shortLin.setGravity(Gravity.RIGHT);

            LayoutParams par = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
            shortLin.setLayoutParams(par);

            TextView s = new TextView(this.getContext());
            s.setTextSize(Float.valueOf(prefs.getString("pref_txtSize", "12")));
            s.setWidth(iF.getResources().getDimensionPixelSize(R.dimen.shortcutWidth));
            s.setPadding(10, 10, 10, 10);

            s.setText(getShortcut(position));

            shortLin.addView(s);

            // Return
            txt.invalidate();
            v.invalidate();
            s.invalidate();

            lin.addView(v);
            lin.addView(txt);
            lin.addView(shortLin);

            return lin;
        }
    };

As you can see, I made a customized ListView. The ArrayAdapter will be added in a different method (not shown here).

Thanks in advance

Adrian

Answer 1

Do you remember about cache?

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

    View view = convertView;
    ViewHolder holder;

    if (view == null) {

        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        view = inflater
                .inflate(R.layout.list_view_home_item, parent, false);

        holder = new ViewHolder();
        holder.title = (TextView) view
                .findViewById(R.id.textView);

        holder.title.setText("blah");
        view.setTag(holder);            
    } else {        
        holder = (ViewHolder) view.getTag();
    }

    return view;

and

    static class ViewHolder {
    TextView title;
}

?