Programmatically Add/Remove items to/from custom listview?

Question

I'm creating a custom list view that is able to add or remove items. I try this code to add a new row item to list view but it says "The method add(String) is undefined for the type ListView".

This is my code:

public class AddActivityCustomList extends ArrayAdapter<String> {

    private final Activity context;
    private final String[] web;

    public AddActivityCustomList(Activity context, String[] web) {
        super(context, R.layout.add_activity_single_list, web);
        this.context = context;
        this.web = web;

    }

    public View getView(final int position, View view, ViewGroup parent) {
        LayoutInflater inflater = context.getLayoutInflater();
        View rowView = inflater.inflate(R.layout.add_activity_single_list,
                null, true);
        TextView txtTitle = (TextView) rowView
                .findViewById(R.id.act_title_single);

        txtTitle.setTypeface(myface);
        txtTitle.setText(web[position]);

        return rowView;

    }

And my Add Button code is this:

add_activity.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                lv.add(add_act_title.getText().toString());
                add_act_title.setText("");
                adapter.notifyDataSetChanged();
                add_act_title.getText();
            }
        });

that has problem in lv.add(...part.What should I do?

Answer 1

The listview displays data from the adapter. Add the new string to the Adapter via it's add function.

Answer 2

    add_activity.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // get the adapter from the listview
            AddActivityCustomList adapter = (AddActivityCustomList) lv.getAdapter();
            // call ArrayAdapter.add, no need to call notifyDataSetChanged as add does this
            adapter.add(add_act_title.getText().toString());
            // clear old title
            add_act_title.setText("");
        }
    });

Answer 3

You can't add data directly to the listview. You need to add the data in the adapter and call notifyDataSetChanged()

Use this

@Override
public void onClick(View arg0) {
    // TODO Auto-generated method stub
    adapter.add(add_act_title.getText().toString());
    adapter.notifyDataSetChanged();
    add_act_title.setText("");
    add_act_title.getText();
}

Answer 4

"The method add(String) is undefined for the type ListView"

Because you are calling add method on ListView instead of Adapter.

How to add a new row item to list view

To add/delete item from ListView use ArrayList as data-source instead of Array because if you use Array and call adapter add method then you will get UnsupportedOperationException.

So make following change in AddActivityCustomList Adapter :

1. Use ArrayList<String> instead of String[] Array.

2. Add new item to adapter as:

AddActivityCustomList adapter=listView.getAdapter();
adapter.add(add_act_title.getText().toString());
adapter.notifyDataSetChanged();