gann-cdf / graphics

import org.gannacademy.cdf.graphics.ui.AppWindow;

import javax.swing.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.KeyEvent;

import java.util.ArrayList;

import java.util.List;

/**

 * This class implements ActionListener so that it can receive button action events

 */

public class SwingButton extends AppWindow implements ActionListener {

    private List<Ball> balls;

    // Swing is the "modern" Java UI system (as opposed to AWT) and all its components are prefixed "J"

    // best practice is to avoid retyping literals (to avoid fat-fingering them)

    private static final String ADD_COMMAND = "add";

    }

    @Override

    protected void setup() {

        balls = new ArrayList<>();

        balls.add(new Ball(getDrawingPanel()));

        // create a new button with the ext "Add Ball"

        addButton = new JButton("Add Ball");

        // associate a keyboard shortcut with the button (Alt+B)

        addButton.setMnemonic(KeyEvent.VK_B);

        // assign a "command" keyword to the button (in case there are many buttons being handled)

        addButton.setActionCommand(ADD_COMMAND);

        // assign ourselves as the actionlistener for this button

        addButton.addActionListener(this);

        /*

         * Position the button on the screen.

         *

         * Note that we use the button's preferred size (which is calculated based on its contents), rather than its

         * width, since it has _no width_, having not yet been added to the layout!

         *

         * Note also that we are turning off the layout manager (setLayout(null)) to allow for absolute positioning

         */

        addButton.setBounds(

                (getDrawingPanel().getWidth() - addButton.getPreferredSize().width) / 2,

                (getDrawingPanel().getHeight() - addButton.getPreferredSize().height) / 2,

                addButton.getPreferredSize().width,

                addButton.getPreferredSize().height

        );

        getDrawingPanel().setLayout(null);

        // actually add the button to the Swing UI hierarchy on top of the drawing panel

        getDrawingPanel().add(addButton);

    }

    @Override

    protected void loop() {

        for (Ball ball : balls) {

            ball.move();

        }

        sleep(10);

    }

    public static void main(String[] args) {

        new SwingButton();

    }

}