How do you create a custom button in lanterna?

Question

I've created a simple terminal app using lanterna that simply displays a custom button. But even though in the custom button's class I extend the Button class and override the Button class' createDefaultRenderer method to return an instance of the Button class' FlatButtonRenderer class, it is displaying the button using the DefaultButtonRenderer class.

Can you help me understand how to create a custom button in lanterna that displays the button using the FlatButtonRenderer?

import java.io.IOException;
import java.util.ArrayList;

import com.googlecode.lanterna.terminal.*;
import com.googlecode.lanterna.screen.*;
import com.googlecode.lanterna.gui2.*;

class Test {
        public static void main(String[] args) {

                DefaultTerminalFactory terminalFactory = new DefaultTerminalFactory();
                Screen screen = null;

                try {
                        screen = terminalFactory.createScreen();
                        screen.startScreen();

                        final WindowBasedTextGUI textGUI = new MultiWindowTextGUI(screen);
                        final Window window = new GUIAppWindow();

                        textGUI.addWindowAndWait(window);
                }
                catch (IOException e) {
                        e.printStackTrace();
                }
                finally {
                        if(screen != null) {
                                try {
                                        screen.stopScreen();
                                }
                                catch(IOException e) {
                                        e.printStackTrace();
                                }
                        }
                }
        }

        private static class GUIAppWindow extends BasicWindow {
                GUIAppWindow() {
                        ArrayList<Window.Hint> hints = new ArrayList<>();
                        hints.add(Window.Hint.CENTERED);
                        setHints(hints);

                        Panel mainPanel = new Panel(new LinearLayout(Direction.VERTICAL));

                        XButton b = new XButton(new String("."));
                        b.addListener(new ButtonHandler("data"));
                        mainPanel.addComponent(b);

                        this.setComponent(mainPanel);
                }

                private class XButton extends Button {

                        public XButton(String label) {
                                super(label);
                        }

                        @Override
                        protected ButtonRenderer createDefaultRenderer() {
                                return new Button.FlatButtonRenderer();
                        }
                }

                private class ButtonHandler implements Button.Listener {
                        final String loc;
                        ButtonHandler(String loc) {
                                this.loc = loc;
                        }
                        public void onTriggered(Button button) {
                                button.setLabel(button.getLabel().equals(".") ? "x" : new String("."));
                        }
                }

        }

}

Answer 1

I believe the correct way to use FlatButtonRenderer is to call setRenderer().

private class XButton extends Button {
    public XButton(String label) { 
        super(label); 
        setRenderer(new Button.FlatButtonRenderer()); 
    } 
}