JButton only appears on mouse?
Here's my code: I pulled out something that I didn't think was necessary. I may have taken some parentheses too, but I'm just trying to show the content I have.
What happens when I run the program, the background image draws (it's a PNG in resources) and only one button appears (my PLAY button) which is the first button - it is automatically selected.
I actually have four buttons, but in my code I have included PLAY and INSTRUCTIONS. The other three don't show up if I don't smoke over them. I know this is probably something weird about the drawing method, but I don't know how to fix it.
If I select a different button and hide the window and then reopen it, that button will only show one. I have to hover my mouse over to display other buttons.
I added super.paint()
to the paint method and I get all my buttons, but the background is gray. I think the problem is super.paint()
painting all my buttons, but g.drawImage(bg, 0, 0, null)
only painting my background, and I cannot do that without painting over the other.
Sorry if this was a mess. I am new to Java and I am having a hard time figuring out what I am trying to say.
public class MainMenu extends JFrame {
private JPanel contentPane;
/**
* Launch the application.
*/
//variables
public static Image bg;
public static void main(String[] args) {
MainMenu mainFrame = new MainMenu();
mainFrame.setSize(FRAME_WIDTH, FRAME_HEIGHT);
mainFrame.setResizable(false);
mainFrame.setLocationRelativeTo(null);
mainFrame.setTitle ("Zumby");
mainFrame.setLayout(null);
// Loads the background image and stores in bg object.
try {
bg = ImageIO.read(new File("zumby.png"));
} catch (IOException e) {
}
mainFrame.setVisible(true);
}
/**
* Overrides the paint method.
* MONDAY
*/
public void paint(Graphics g)
{
// Draws the img to the BackgroundPanel.
System.out.println("paint");
g.drawImage(bg, 0, 0, null);
}
/**
*/
public MainMenu() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 800, 500);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
contentPane.setOpaque(false);
setContentPane(contentPane);
contentPane.setLayout(null);
//create buttons
JButton btnPlay = new JButton("PLAY");
btnPlay.setBackground(Color.BLACK);
btnPlay.setForeground(Color.WHITE);
btnPlay.setFont(font);
btnPlay.setBorder(border);
btnPlay.setFocusPainted(false);
//if "Play" is clicked
btnPlay.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent click) {
setVisible(false);
new GamePlay(); //opens up GamePlay window
}
});
btnPlay.setBounds(600, 64, 141, 61);
contentPane.add(btnPlay);
JButton btnInstructions = new JButton("INSTRUCTIONS");
btnInstructions.setBounds(600, 160, 141, 61);
btnInstructions.setBackground(Color.BLACK);
btnInstructions.setFocusPainted(false);
// btnInstructions.setEnabled(true);
contentPane.add(btnInstructions);
repaint();
pack();
setVisible(true);
}
}
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Swing uses the concept of "layering" for drawing ...
paint
calls paintComponent
, paintBorder
and paintChildren
. By overriding paint
and not calling super.paint
, you prevented the component from painting it in different layers.
In Swing, it is preferable to use it paintComponent
to create a custom paint that allows you to paint under any other components that can be added to the component.
public class TestPaint01 {
public static void main(String[] args) {
new TestPaint01();
}
public TestPaint01() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private Image backgroundImage;
public TestPane() {
try {
BufferedImage background = ImageIO.read(new File("/path/to/image.jpg"));
//backgroundImage = background.getScaledInstance(-1, background.getHeight() / 4, Image.SCALE_SMOOTH);
backgroundImage = background;
} catch (IOException ex) {
ex.printStackTrace();
}
setLayout(new GridBagLayout());
add(new JButton("Hello"));
}
@Override
public Dimension getPreferredSize() {
return backgroundImage == null ? super.getPreferredSize() : new Dimension(backgroundImage.getWidth(this), backgroundImage.getHeight(this));
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int x = (getWidth() - backgroundImage.getWidth(this)) / 2;
int y = (getHeight() - backgroundImage.getHeight(this)) / 2;
g.drawImage(backgroundImage, x, y, this);
}
}
}
You can find a Closer Look at Drawing Engine and Painting in AWT and Swing .
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I think this is because you are overriding the draw method. Better to override the repaint, then call super.repaint (); Like this:
public void repaint(Graphics g)
{
super.repaint(g);
// Draws the img to the BackgroundPanel.
System.out.println("paint");
g.drawImage(bg, 0, 0, null);
}
Then the components are also redrawn.
But if all you want to do is show the image as a background, see here.
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