Cant get JButton to appear in the game

[Zane Adickes]

Im working on a turn based strategy game. When a unit is selected on the field I need its available actions to be displayed. Im trying to use JButtons to display the actions so if you were to click the "Move" button you would be enabled to select a destination for that unit. The code I have currently refuses to display and JButtons. I hope you guys can help me out.

Here are a few points that might help you help me:
In the Games constructor it creates a JFrame and JPanel
it sets the JPanel equal to the frames content pane.
The game creates a level.
In the levels "setUp" method it is creating a JButton and passing it to the Games "addComponent" method where it is adding the component to the content pane. (this in itself seems like it may be a little messy to me).

The code compiles and runs fine but I get no JButton.

Thank You!

public class Game extends Canvas implements Runnable{
	private static final long serialVersionUID = 1L;
	
	//graphics
	public BufferStrategy buffy;
	BufferedImage image;
	Screen screen;
	
	public Boolean running = false;
	public Boolean playerTurn = false;
	
	public InputManager input;
	public JPanel panel;
	public Level level;
	
	public static final int HEIGHT = 452;
	public static final int WIDTH = 768;
	
	public Game() {
		JFrame frame = new JFrame("Grid Wars...foundation under construction....");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		panel = (JPanel) frame.getContentPane();
		panel.setPreferredSize(new Dimension(WIDTH, HEIGHT));
		panel.setLayout(null);
		panel.setOpaque(false);
		panel.add(this);
		setBounds(0,0,WIDTH,HEIGHT);
		
		frame.setResizable(false);
		frame.pack();
		frame.setLocationRelativeTo(null);
		frame.setVisible(true);
		requestFocus();
		
		createBufferStrategy(2);
		buffy = getBufferStrategy();
		image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
		screen = new Screen(WIDTH, HEIGHT);
		input = new InputManager(this);
		level = new Level(WIDTH, HEIGHT, input, this);
	}
	
	public void start() {
		running = true;
		new Thread(this).start();
	}
	
	public void run() {
		System.out.println("started");
		final double TICKS = 30.0;
		final double UPDATE_INTERVAL_NS = 1000000000 / TICKS;
		double pastUpdateNS = System.nanoTime();
		
		int updateCount = 0;
		int frameCount = 0;
		
		final double FRAPS = 60.0; 
		final double RENDER_INTERVAL_NS = 1000000000 / FRAPS;
		double pastRenderNS = System.nanoTime();
		
		int pastSecondNS = (int) (pastUpdateNS/1000000000);
		
		while(running) {
			double nowNS = System.nanoTime();
			
			if(nowNS - pastUpdateNS >= UPDATE_INTERVAL_NS) {
				update();
				pastUpdateNS += UPDATE_INTERVAL_NS;
				updateCount++;
			}
			
			float interp = Math.min(1.0f, (float) ((nowNS - pastUpdateNS) / UPDATE_INTERVAL_NS) );
			render(interp);
			pastRenderNS += RENDER_INTERVAL_NS;
			frameCount++;
			
			int thisSecondNS = (int) (pastUpdateNS/1000000000);
			if (thisSecondNS > pastSecondNS) {
				System.out.println("TICKS: "+updateCount+" | FRAPS: "+frameCount);
				updateCount = 0;
				frameCount = 0;
				pastSecondNS = thisSecondNS;
			}
			
			while( nowNS - pastRenderNS < RENDER_INTERVAL_NS && nowNS - pastUpdateNS < UPDATE_INTERVAL_NS) {
				try { Thread.sleep(1); } catch(Exception e) {};
				nowNS = System.nanoTime();
			}
		}
	}
	
	public void update() {
		input.update();
		level.update();
	}
	
	public void render(float interp) {
		level.render(screen, interp);
		
		image = screen.getImage();
		Graphics g = buffy.getDrawGraphics();
		g.drawImage(image, 0, 0, null, null);
		g.dispose();
		buffy.show();
	}
	
	public void addComponent(Component component) {
		panel.add(component);
	}
	
	public static void main(String[] args) {
		
		Game game = new Game();
		game.start();
	}
}

public class Level {
	JButton move = new JButton("move");
	
	//Level attributes
	public final int GRID_SIZE = 10;
	public final int Q_SIZE = 32;
	public final int WIDTH;
	public final int MAP_HEIGHT;
	public final int HEIGHT;
	public float gx;
	public float gy;
	
	public InputManager input;
	public Game game;
	public Image levelImage;
	
	//Entities
	public ArrayList<Mobile> mobiles;
	public ArrayList<Point> entityLocs;
	private Mobile activeUnit;
	public SelectionSquare square;
	
	public Level(int width, int height, InputManager input, Game game) {
		this.input = input;
		this.game = game;
		WIDTH = width;
		HEIGHT = height ;
		MAP_HEIGHT = height-100;
		mobiles = new ArrayList<Mobile>();
		setUp();
	}
	
	public void setUp(){
		levelImage = new ImageIcon("images/levelbackground.png").getImage();
		addMobile(new Granadier(64,64,this,input));
		addMobile(new Granadier(128,128,this,input));
		addMobile(new Granadier(256,256,this,input));
		
		//make button
		ImageIcon moveBImage = new ImageIcon("images/movebutton.png");
		JButton moveB = new JButton(moveBImage);
		moveB.addActionListener(new MoveCommand());
		moveB.setIgnoreRepaint(true);
		moveB.setFocusable(false);
		moveB.setBorder(null);
		moveB.setContentAreaFilled(false);
		moveB.setIcon(moveBImage);
		moveB.setBounds(25, 25, 0, 400);
		game.addComponent(moveB);
	}
	
	public void update() {
		if (input.pressed){
			if(input.x > Q_SIZE && input.x < WIDTH-Q_SIZE && input.y > Q_SIZE && input.y < MAP_HEIGHT) {
				if (input.x < Q_SIZE*11 || input.x >= Q_SIZE*13){
					findGridPoint();
				}
			}
		}
		
		if(square != null) {
			square.update();
		}else if(square == null && input.pressed == true) {
			square = new SelectionSquare(gx,gy,this,input);
		}
		for (int x = 0; x < mobiles.size(); x++) {
			Mobile m = mobiles.get(x);
			m.update();
		}
	}
	
	public void render(Screen screen, float interp) {
		screen.render(levelImage, 0, 0);
		for (int x = 0; x < mobiles.size(); x++) {
			Mobile m = mobiles.get(x);
			if (m.moving) {
				screen.interpRender(m, interp);
			}else{
				screen.render(m);
			}
		}
		if(square != null){
			screen.render(square);
		}
	}
	
	public void findGridPoint () {
		gx = input.x - (input.x % Q_SIZE);
		gy = input.y - (input.y % Q_SIZE);
	}
	
	public void addMobile(Mobile m) {
		mobiles.add(m);
	}
	
	public void setActiveUnit(Mobile m){
		activeUnit = m;
	}
	
	public void clearActiveUnit(){
		activeUnit = null;
	}

	class MoveCommand implements ActionListener {
		public void actionPerformed(ActionEvent event){
		}
	}
	
	class AttackCommand implements ActionListener {
		public void actionPerformed(ActionEvent event){
		}
	}

}

[Stephan van Hulst]

So, what happened when you remove the setIgnoreRepaint() and setContentAreaFilled() method calls?

Welcome to CodeRanch!

[Zane Adickes]

I've tried commenting out both and it didn't help :/.

Thanks You!

[Devarsh Shah]

Try this :

  public void addComponent(Component component) {  
         panel.add(component);  
         panel.repaint();
  }  

[Zane Adickes]

Ok. Thanks, Devarsh. I'll give this a try first thing after I get off work. I'm wondering though, the content pane is "repainted" ever time render() is run. Would this mean I need to repaint the button every time through the loop as well because that I have tried a few different ways but still with no results

[Michael Dunn]

so many things just plain wrong

1) *always* start a swing GUI in the Swing thread (EDT), via SwingUtilities.invokeLater(...)
2) *never* *ever*, have Thread.sleep() in the same thread where repainting or event listening occurs,
separate thread or (usually) better to use a Swing Timer.
3) not sure if you're using 'extends Canvas', but don't use it in Swing, use a JPanel and its paintComponent()

that should do for starters, but to answer your initial question/problem, in Swing, any time you add/remove
components from a visible container, this is the sequence:

[container].add(...);//or remove(...)
[container].revalidate();
[container].repaint();//this line sometimes not necessary, but best to include it always.