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Thread: extended JPanel is empty

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    Default extended JPanel is empty

    Hi,
    I made a extended JPanel, but when i call on it in another class the panel shows but its empty... This is my code:
    import java.awt.*;
    import java.awt.event.*;
    import javax.swing.*;
    public class FindPanel extends JPanel
    { 
        JRadioButton biologyClass = new JRadioButton("Biology");
        ...make a radiobutton for each subject
     
        ButtonGroup classButtonGroup = new ButtonGroup();
        public void classesJPanel() {
            //add to button group
            classButtonGroup.add(biologyClass);
            ... add all the subjects to buttongroup
            //add to panel
            add(biologyClass);
            ...add all the subjects
            }
     
     
     
    }

    when i call on the code this is what i am using:
    FindPanel jPanel1 = new FindPanel();

    Thanks
    Joel


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    Default Re: extended JPanel is empty

    I should also point out that im trying to call it in an applet. I called it in a normal JFrame and it worked fine, it just doesnt like the applet...

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    Default Re: extended JPanel is empty

    You do not have a constructor for your FindPanel Class. You need an overide constructor

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    Default Re: extended JPanel is empty

    How do i make an override constructor? What is it exactly?

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    Default Re: extended JPanel is empty

    JPanel is your superclass, in this case, so you need to insert the code...
    super(String title)
     
    //title is what the dialog box will be named in its title bar
    ...before your other code.

    You also need to surround everything you have so far except the class name in...
    public FindPanel() {
    //your other code here
    }

    So, when it's all put together, the end result should be something like this:
    public class FindPanel extends JPanel
    {
       public FindPanel()
       {
     
          super(String title)
          //Note that you will not actually type "String title"; instead you
          //should type what you want the dialog to be titled when you open it
     
          //Put all your other code here, like the JRadioButton and ButtonGroup, etc.
          //Don't include the "public void classesJPanel()" part, just remove those brackets
          //The "super" constructor already creates a JPanel, and you're just customizing it
     
       }
    }
    Hopefully I got my meaning through... Sorry if it's unclear.
    Last edited by snowguy13; November 26th, 2011 at 05:43 PM. Reason: To increase clarity

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