[Solved] Bad performance of custom Listview, Listview Items Name gets converted from Database

Question

You are doing quite a lot that is not necessary. I reduced the code and added some comments. In short:

Use the position to find which data should be fetched (it could also be a prefetched list which would reduce the fetch from database to 1 query)
You should use the ViewHolder pattern to recycle and reuse views -> quite some performance improvement
You need to do “static” stuff outside the getView() method because stuff like loading a Typeface is quite slow.

Hope the below code helps you!

public class RezeptArrayAdapter extends ArrayAdapter<String> {

    public final Context context;
    public final String[] values;
    final DBHandler_Rezepte db_Rzpt;
    //TYPEFACE///////////
    Typeface tf;


    public RezeptArrayAdapter(Context context, String[] values) {
        super(context, R.layout.list_rezepte, values);
        this.context = context;
        this.values = values;

        // Do "static/reusable" stuff here
        // DatenBank Abfrage Angepasst auf den Array "context" View
        db_Rzpt = new DBHandler_Rezepte(context);
        //TYPEFACE///////////
        tf = Typeface.createFromAsset(context.getAssets(), "fonts/OFLGoudyStMTT.ttf");
    }

    // will be called quite often! Make it fast as possible!
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        //Einzelabfrage der Datenbank Ratings damit Sie weiter unten verarbeitet werden können
        ConDB_Rezepte data = db_Rzpt.getConDB_Rezepte(position);

        // To not do too much at once this tip for later: Use the ViewHolder pattern
        View rowView = inflater.inflate(R.layout.list_rezepte, parent, false);
        TextView textView = (TextView) rowView.findViewById(R.id.label);
        ImageView imageView = (ImageView) rowView.findViewById(R.id.logo);
        RatingBar ratingbar1 = (RatingBar) rowView.findViewById(R.id.ratingBar1);

        //stellt ein das man die Ratingbar nicht clicken kann, somit bleibt die Steuerung erhalten. Sonst ist die Liste nicht mehr clickbar
        ratingbar1.setIsIndicator(true);

        textView.setText(values[position]);

        textView.setTypeface(tf);


        // Change icon based on name
        String pos = values[position];

        // data should contain the information which icon should be shown!
        //int KuchenIcon = R.drawable.ic_kuchen;
        //int MuffinIcon = R.drawable.ic_muffin;
        //int PlaetzchenIcon = R.drawable.ic_plaetzchen;
        //int ApfelkandiertIcon = R.drawable.ic_apfelkandiert;
        //int OthersIcon = R.drawable.ic_others;

        // apply values/data to the view
        imageView.setImageResource(data.getIcon());
        ratingbar1.setRating(data.getrating());

        return rowView;
    }

}

Update:

For the problem with the icon, the solution might be pretty easy: You can get the icon by name. All you need to do is storing the name of the icon in the database.

When you have done that, you can use the following method to load the drawables:

public int getDrawableResource(String drawableName){
    return getResources().getIdentifier(drawableName, "drawable", getActivity().getPackageName());
}

So all you need is to store the icon name in the database so that data.getIcon() returns the resource id you get by using the above method.

Accepted Answer