so after solving my first error due to the help of Hovercraft I finally started coding and getting stuff ready for my actual project. However, when I tried to add the label it now just shows me nothing at all, I mean if I remove the label and add any other stuff such as a button or so, it would show me the button but the moment I add the jlabel to the code it just gives me a complete blank screen no matter what the property of the label be. The code of the project is as follow:
Main Frame:
public class Parking_Mania {
public static void main(String []args)throws Exception
{
new GameFrame("Paking Mania");
}
}
Game Frame:
public class GameFrame extends JFrame{
File info=new File("information.txt");
public GameFrame(String name) throws IOException
{
if(!info.exists())
{
info.createNewFile();
}
this.setTitle(name);
this.setSize(640,510);
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setResizable(false);
this.setVisible(true);
Frames frame=new Frames();
this.add(frame);
frame.panel.show(frame, "opening");
}
}
Panel Class that handles changing different panels:
public class Frames extends JPanel{
CardLayout panel= new CardLayout();
public Frames()
{
this.setLayout(panel);
Opening op=new Opening(this);
//nxtframe nf= new nxtframe(this);
this.add(op, "opening");
//this.add(nf, "nt");
}
}
Finally the panel which should be showing itself on the frame:
public class Opening extends JPanel{
private Frames f;
private JLabel bg=new JLabel();
//private JLabel helpframe=new JLabel();
private JButton play=new JButton();
/*private JButton help=new JButton();
private JButton helpclose=new JButton();
private ImageIcon background;*/
public Opening(final Frames f){
this.f=f;
this.setBackground(Color.BLACK);
//this.add(bg);
this.add(play);
//bg.setIcon(new ImageIcon(getClass().getResource("/bg.jpg")));
}
}
Components should be added to the frame before the frame is made visible.
Start with the working examples found in the Swing tutorial. The tutorial covers all the basics of Swing.
I would especially start with the tutorial on How to Use CardLayout for the first demo code to understand and modify.
The tutorial will show you how to better structure your code so that you don't keep extending panels, just to add components to a panel.
Related
I am trying to make a panel showing a printed statement "Hello World!" and an OK button. Neither will show up on the panel and I have no idea why. I started with a block of code that was supposed to create just a blank popup. The blank popup worked great. I can't add the string or button and see them. I have tried calling paintComponent. I have tried adding the content to the panel. Does anyone know what I am missing?
Here is my code
package painting;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class SwingPaintDemo1 {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
private static class SwingPaintDemo extends JPanel{
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawString("Hello World!", 20,30);
}
}
private static void createAndShowGUI() {
System.out.println("Created GUI on EDT? "+
SwingUtilities.isEventDispatchThread());
JFrame f = new JFrame("Swing Paint Demo");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(250,250);
f.setVisible(true);
JButton okbutton = new JButton("OK");
ButtonHandler listener = new ButtonHandler();
okbutton.addActionListener(listener);
SwingPaintDemo displayPanel = new SwingPaintDemo();
JPanel content = new JPanel();
content.setLayout(new BorderLayout());
content.add(displayPanel, BorderLayout.CENTER);
content.add(okbutton, BorderLayout.SOUTH);
}
private static class ButtonHandler implements ActionListener{
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
}
}
You forgot to add the JPanel to the JFrame. Just add the following line at the bottom of your createAndShowGUI() method:
f.add(content);
I would also recommend moving your f.setVisible(true); line to the bottom of the method just to be safe. When you make the frame visible, the component tree is set up to take into account all the components added to the JFrame. If you add more components after that, you will need to do either manually revalidate the tree or do something that triggers an automatic revalidation. I'm assuming you're not revalidating your tree anywhere, so you should move f.setVisible(true); to after all the components are added.
i have this problem and yes i saw that other people had the problem to but i not realy able to compare there code to mine and see the problem that way so i hope u can help me.
i use intellij to write my code and use there gui desinger to make gui's but when i added a button i didnt get it to display untill i hover it with a mouse and the possitions are wrong and i cant realy get it to work. here are the classes
// this is the jpanel class
public class paintMenu extends JPanel{
public JPanel menuPanel;
public JButton newGameButt;
public JButton loadGameButt;
public JButton helpbutt;
public JButton optionsButt;
public JButton info;
public JButton quitButt;
public paintMenu(){
add(newGameButt);
add(loadGameButt);
add(helpbutt);
add(info);
add(optionsButt);
add(quitButt);
setVisible(true);
}
//this is de jframe class
public class jframepainter extends JFrame {
paintMenu menupaint = new paintMenu();
public jframepainter(){
//main frame settings
setTitle("Kingdom V " + Reference.version);
setSize(Reference.width, Reference.height);
setResizable(false);
setLocationRelativeTo(null);
setVisible(Kingdom.vissible);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//draw jpnael
getContentPane().add(menupaint);
}
Try setting the JFrame to visible after you add your JPanel to it. Also you may want to call this.pack() after you add your JPanel.
//main frame settings
setTitle("Kingdom V " + Reference.version);
setSize(Reference.width, Reference.height);
setResizable(false);
setLocationRelativeTo(null);
//draw jpnael
getContentPane().add(menupaint); //Moved this before setting Visible
this.pack(); // call pack before setting visible
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(Kingdom.vissible);
I don't know what the Kingdom class is, but i can assume that vissible is a typo and may be causing a compile-time error. You didn't clearly describe your problem.
This is not a repeat question. Yes there are similar, but none have provided a working answer.
public class Tool extends JPanel implements ActionListener{
public JPanel Panel;
public Tool() {
}
public void show(){
displayStuff();
Panel.setVisible(true);
revalidate();
repaint();
}
}
Tool MyTool = new Tool();
JPanel Master = new JPanel();
JPanel Dash = = new JPanel();
JTabbedPane Tabs = new JTabbedPane();
JTabbedPane Tabs.addTab("Dash", Dash);
JTabbedPane Tabs.addTab("Tool", MyTool.Panel);
Master.add(Tabs);
The real code is much more complex. But the basic issue is that when changes occurs on MyTool.Panel as a result of user pressing some buttons.
MyTool.Panel does NOT get repainted until I use mouse to move Master.
How can I force it to repaint?
Its not a perfect solution but you can validate and redraw the entire application, thats what I have done in the past. I've used something like
class MyPanel extends JPanel{
public void doRedraw(){
getTopLevelAncestor().revalidate();
getTopLevelAncestor().repaint();
}
}
Hope this helps.
I need to write a simple tennis game.
To move between different windows(panel with main menu, panel with game, panel with settings) I decided to use inner classes extends JPanel and replace it when some events like start new game occurs.
but the problem is - it doesn't see my inner class. I mean I add it to JFrame
mainframe.add(new MainMenuPanel());
but there is nothing on the screen when I run program. What's the problem?
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class MainFrame{
JFrame mainframe;
public static void main(String[] args){
new MainFrame();
}
public MainFrame() {
mainframe = new JFrame();
mainframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainframe.setSize(300, 400);
mainframe.setTitle("X-Tennis v0.1");
mainframe.add(new MainMenuPanel());
mainframe.getContentPane().setLayout(new GridLayout());
mainframe.getContentPane().setBackground(Color.WHITE);
mainframe.setVisible(true);
}
public class MainMenuPanel extends JPanel {
JPanel mainmenupanel;
JLabel label1;
JButton btnNewGame,btnJoinGame;
ImageIcon iconNewGame,iconJoinGame;
public MainMenuPanel(){
mainmenupanel = new JPanel();
label1 = new JLabel("X-TENNIS");
label1.setFont(new Font("Comic Sans MS",Font.ITALIC,20));
label1.setForeground(Color.BLUE);
btnNewGame = new JButton("New Game", iconNewGame);
btnNewGame.setFocusPainted(false);
btnNewGame.addActionListener(
new ActionListener() {
public void actionPerformed(ActionEvent e){
JOptionPane.showMessageDialog(mainframe, "New game");
//delete current panel and add another to mainframe
}
}
);
btnNewGame.setPreferredSize(new Dimension(140,30));
btnJoinGame = new JButton("Join game",iconJoinGame);
mainmenupanel.add(label1);
mainmenupanel.add(btnNewGame);
}
}
}
There is no need for mainmenupanel within the MainMenuPanel class as MainMenuPanel is a JPanel itself
Simple add all the components in MainMenuPanel directly to itself
You create a new JPanel, mainmenupanel, inside MainMenuPanel but never add that to the container itself. You could do
add(mainmenupanel);
If you intend for this JPanel to occupy the full area of the parent, then you can simply add your components directly to your instance of MainMenuPanel as indicated by #Mad
First you should add your component to the ContentPane. In Swing, all the non-menu components displayed by the JFrame should be in the ContentPane.
mainframe.getContentPane().add(new MainMenuPanel());
Edit: I was wrong about the content pane, see #MadProgrammer comment.
Then you have to add the JPanel that you create in MainMenuPanel to the MainMenuPanel instance itself.
add(mainmenupanel);
But you should probably get rid of that intermediary container itself and add your labels to the MainMenuPanel instance itself:
add(label1);
add(btnNewGame);
mainmenupanel.add(label1);
mainmenupanel.add(btnNewGame);
try this :
super.add(label1);
super.add(btnNewGame);
I have this piece of code and read that validate can refer to laying out a container's subcomponents. "Layout-related changes, such as setting the bounds of a component, or adding a component to the container, invalidate the container automatically." (source: javadoc).
However, I see no difference whatsoever between keeping validate() or removing it from this little piece of code.
Can you show me a convincing example where you can see distinct behaviour in two cases (with or without validate) to prove a point? Any other comments/advice appreciated.
public class Sw1
extends JApplet
{
JLabel lbl;
public void init()
{
lbl = new JLabel ("a label");
JPanel pan = (JPanel) getContentPane ();
pan.add(lbl);
validate();
}
}
Here is the program after I intended the push of a button to add a label. It renders an exception when I push the button:
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
public class Sw_test
extends JApplet
implements ActionListener
{
JLabel lbl;
JButton bt ;
JPanel pan ;
JLabel l;
public void init()
{
lbl = new JLabel ("label 1");
bt = new JButton ("go ahead, press me");
bt.addActionListener(this);
JPanel pan = (JPanel) getContentPane ();
pan.setLayout(new FlowLayout());
pan.add(lbl);
pan.add(bt);
validate();
}
public void actionPerformed(ActionEvent ev)
{
l = new JLabel("new label");
pan.add(l);
}
}
You would need to call it if you add a component to a panel after it has been initialized and made visible.
Try adding a button to your applet, and on the click of the button, add a new label to the applet.
i will quote the API:
The validate method is used to cause a container to lay out its subcomponents again. It should be invoked when this container's subcomponents are modified (added to or removed from the container, or layout-related information changed) after the container has been displayed.
so as you see, it is important if you modify your layout, AFTER it has been initialized.
That is the reason why you don´t see any difference
btw: here is your example :
public class TestFrame extends JFrame{
private JButton b = new JButton();
public TestFrame() {
this.setLayout(new GridLayout(5,5));
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.add(b);
b.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
TestFrame.this.add(new JLabel("whatever"));
//try it with and without
//validate();
}
});
this.setSize(300, 300);
this.setVisible(true);
}
public static void main(String[] args) {
new TestFrame();
}
}