Question

I am using a ListView with a custom row wich has 2 TextViews. I have made my own Adapter and it’s working fine with my list. Now, I want the user to input 2 texts and then insert a new row (with user’s inputs) in my ListView. I’ve tried with add method but I’m getting UnsupportedOperationException. Do I have to override add method also? if so, what do I need to do in it? Thank you.

I’m going to paste a fragment of the code. Let me know if you need further information.

public class ChatAdapter extends ArrayAdapter<ChatItems>{

Context context;
int textViewResourceId;
ChatItems[] objects;


public ChatAdapter(Context context, int textViewResourceId,
        ChatItems[] objects) {
    super(context, textViewResourceId, objects);

    this.context = context;
    this.textViewResourceId = textViewResourceId;
    this.objects = objects;
}


@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;
    ChatHolder holder = null;


    if(row == null){
    LayoutInflater inflater =  ((Activity)context).getLayoutInflater();
    row = inflater.inflate(textViewResourceId, null);

    holder = new ChatHolder();
    holder.user = (TextView) row.findViewById(R.id.textUser);
    holder.msg = (TextView) row.findViewById(R.id.textText);

    row.setTag(holder);

    }else
        holder = (ChatHolder) row.getTag();


    ChatItems items = objects[position];
    holder.msg.setText(items.msg);
    holder.user.setText(items.user);


    return row;

}
static class ChatHolder{
    TextView user;
    TextView msg;
}

}

public class ChatItems {

String user;
String msg;

public ChatItems(String user, String msg){
    this.user = user;
    this.msg = msg;
}

}

Answer 1

If you want to add another items to your ArrayAdapter use ArrayList instead of Array as your back-end data holder. If you are using Array, than ArrayAdapter will use List internally which can’t be modified later.

Remove objects field from your ChatAdapter.

Rewrite your constructor like

public ChatAdapter(Context context, int textViewResourceId, List<ChatItems> objects) {
    super(context, textViewResourceId, objects);
    this.context = context;
    this.textViewResourceId = textViewResourceId;
}

to get the item in getView() use ChatItems items = getItem(position) instead of ChatItems items = objects[position];

And finally create your adapter like adapter = new ChatAdapter(this, R.layout.chat_item, new ArrayList<ChatItems>());