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Thread: need help with ActionListener,JPanel,JFrame

  1. #1
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    Default need help with ActionListener,JPanel,JFrame

    hey everyone,

    can someone help me on this problem
    this is the problem, i have one instance of JFrame that implements an ActionListener
    and from this JFrame i need to call one instance of JPanel that also implements an ActionListener

    i have write these code below for testing purpose, and i still dont know what wrong with these code
    somehow i was unable to call the JPanel into the JFrame

    AL.java

    import java.awt.*;
    import java.awt.event.*;
    import javax.swing.*;
     
    public class AL extends JFrame implements ActionListener {
    	public JMenuBar menuBar;
    	public JMenu fileMenu, helpMenu;
    	public JMenuItem newAction, exitAction, tombolAction;
     
    	public AL() {
    		menuBar = new JMenuBar();
        	setJMenuBar(menuBar);
     
        	fileMenu = new JMenu("File");
            menuBar.add(fileMenu);
     
            newAction = new JMenuItem("New");
            exitAction = new JMenuItem("Exit");
            fileMenu.add(newAction);
            fileMenu.addSeparator();
            fileMenu.add(exitAction);
     
            newAction.addActionListener(this);
            exitAction.addActionListener(this);
     
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            setSize(300, 300);
            setLocationRelativeTo(null);
            setTitle("Save The Villages");
            setResizable(false);
            setVisible(true);    
    	}
     
    	public void actionPerformed(ActionEvent event) {
    		if(event.getSource()==newAction) {
    			System.out.println("You have clicked on the new action");
    			add(new AL_test());
    		}
    		if(event.getSource()==exitAction) {
    			System.exit(0);
    		}
    	}
     
    	public static void main(String[] args) {
            new AL();
        }
    }

    AL_test.java

    import java.awt.*;
    import java.awt.event.*;
    import javax.swing.*;
     
    public class AL_test extends JPanel implements ActionListener {
    	JButton btn1 = new JButton();
     
    	public AL_test() {
    		btn1 = new JButton("baru");
    		add(btn1);
    		btn1.addActionListener(this); 
    	}
     
    	public void actionPerformed(ActionEvent event) {
    		if(event.getSource()==btn1) {
    			System.out.println("You have clicked on button");
    		}
    	}
    }

    can someone please enlighten me, what am i doing wrong

    and sorry for the bad English


  2. #2
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    Default Re: need help with ActionListener,JPanel,JFrame

    never mind, i already find out that im missing JFrame.show();
    under JFrame.add(new AL_test());

  3. #3
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    Default Re: need help with ActionListener,JPanel,JFrame

    Quote Originally Posted by amahara View Post
    never mind, i already find out that im missing JFrame.show();
    under JFrame.add(new AL_test());
    JFrame.show is deprecated and a bit overkill, you can just call pack() and the JFrame will repack all of its container components.

  4. #4
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    Default Re: need help with ActionListener,JPanel,JFrame

    Quote Originally Posted by copeg View Post
    JFrame.show is deprecated and a bit overkill, you can just call pack() and the JFrame will repack all of its container components.
    thanks for the info copeg, i tried using pack() as you suggested, but somehow it resize my JFrame dimension
    so can i stop it from resizing itself?

    and just a quick question, can i use KeyListener in AL_test.java?
    because when i try it, its not working

     
    public AL_test() {
    	btn1 = new JButton("baru");
    	add(btn1);
    	btn1.addActionListener(this); 
    	KeyListener listener = new KeyListener() {
    		public void keyPressed(KeyEvent e) {
    			int key = e.getKeyCode();
          			if (key == KeyEvent.VK_SPACE) {
                				System.out.println("You have clicked on SPACE");
    	        		}
          		}
    		public void keyReleased(KeyEvent e) {}
    		public void keyTyped(KeyEvent e) {}
    	};
    	addKeyListener(listener);
    }

  5. #5
    Administrator copeg's Avatar
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    Default Re: need help with ActionListener,JPanel,JFrame

    It will resize because it recalculates the layout based upon the preferred sizes of all it components. You can play with setting the preferred size of the panel to prevent this.

    The keyListener code won't compile because you have not implemented the entire interface. You can use a KeyAdapter which makes implementing the interface easier. In addition, the component you wish to listen for event must have focus, so after you call pack you need to call requestFocus on the appropriate component

  6. The Following User Says Thank You to copeg For This Useful Post:

    amahara (February 3rd, 2010)

  7. #6
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    Default Re: need help with ActionListener,JPanel,JFrame

    wow, thanks for your explanation copeg, this solved the problem

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