Question

I’m coding a really basic check list app. The user can add tasks and then check them off. But for some reason, when the user check an item – the position in the list changes. Here are a couple of screenshots to show what I mean. The code of my ListAdapter follows:

(The Number at the end of the list item is it’s position. e.g. Do Laundry [False]0 is item at position 0.)

CODE

class TaskListAdapter extends ArrayAdapter<Task> implements OnCheckedChangeListener
    {
        Activity        context;
        View            recycledView;
        ViewAccessor    viewAccessor;
        CheckBox        checkbox;
        int             position;

        public TaskListAdapter(Activity context, int resource, int textViewResourceId, List<Task> objects) {
            super(context, resource, textViewResourceId, objects);
            this.context = context;
        }


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

            this.recycledView   = convertView;

            if(recycledView == null)
            {
                LayoutInflater inflater = context.getLayoutInflater();

                recycledView        = inflater.inflate(R.layout.checkview, null);

                this.viewAccessor   = new ViewAccessor(recycledView);
                this.recycledView.setTag(this.viewAccessor);

                this.checkbox   = (CheckBox) recycledView.findViewById(R.id.cbTaskCompleted);
                this.checkbox.setOnCheckedChangeListener(this);
                this.checkbox.setTag((Integer) position);

            }else
            {
                viewAccessor = (ViewAccessor) this.recycledView.getTag();
                this.checkbox = viewAccessor.getCheckBox();
            }

            this.checkbox.setText( taskList.get(position).toString()+String.valueOf(position) );
            this.checkbox.setChecked( taskList.get(position).isCompleted );

            return recycledView;
        }

        public void onCheckedChanged(CompoundButton buttonView,boolean isChecked) {

            Task taskUnderConsideration = taskList.get( (Integer) buttonView.getTag() ) ;
            taskUnderConsideration.setCompleted(isChecked);
            buttonView.setText(taskUnderConsideration.toString()+buttonView.getTag().toString());
        }
    }

    class ViewAccessor
    {
        View v;
        CheckBox cb = null;

        ViewAccessor(View v)
        {
            this.v = v;
        }

        CheckBox getCheckBox()
        {
            if(cb==null)
                cb = (CheckBox) v.findViewById(R.id.cbTaskCompleted);
            return cb;
        }


    }

Answer 1

If you want to show simple row (with single TextView and CheckBox), I’ll recommend you to use ListView‘s method:

listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);

It’ll automatically show the (built-in) CheckBox with the TextView.