Article View: borland.public.jbuilder.java.language
Article #15047Re: When getParent() is available ?
From: Matt Welsh
Date: Tue, 13 Jul 1999 00:00
Date: Tue, 13 Jul 1999 00:00
71 lines
2188 bytes
2188 bytes
Without seeing your code I'm pretty sure that what's going on is that
you haven't added it to a container so it has no parent.
The following bit of code demonstrates this:
package untitled13;
import java.io.*;
import java.util.*;
import java.awt.*;
public class Bug1 extends Frame{
public Bug1() {
MyPanel p = new MyPanel();
p.printParent();
add(p);
p.printParent();
}
public static void main(String args[]) {
Bug1 bug = new Bug1();
}
}
class MyPanel extends Panel {
public MyPanel() {
System.out.println(this.getParent());
}
public void printParent() {
System.out.println(this.getParent());
}
}
The output is :
[c:\jbuilder3\myclasses]java untitled13.Bug1
null
null
untitled13.Bug1[frame0,0,0,0x0,invalid,hidden,layout=java.awt.BorderLayout,resizable,title=]
Until the add statement in the Frame is reached, the panel is
unparented.
-Matt
Christophe wrote:
>
> Hi
>
> I've done a component derived from Panel. I need to know if I'm executing in
> an applet or in a stand alone application. To do that I use the getParent
> function and test if I can assigned it to a java.applet.Applet and this
> until getParent() is null. It's running well.
> But if i use it in the constructor, it failed, the parent seems to be not
> available.
> Where must I put this code? I've tried to override the validate method but
> it failed so.
>
> Thanks in advance.
--
/**
* Matt Welsh
* Borland
* R&D Engineer, JBuilder
*
* @param email mwelsh@Borland.com
* @param WWW http://www.borland.com
* @deprecated http://www.inprise.com
*/
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f74b3,4151ac4308879afd X-Google-Attributes: gidf74b3,public From: Matt Welsh <mwelsh@inprise.com> Subject: Re: When getParent() is available ? Date: 1999/07/13 Message-ID: <378BB900.FEAA4205@inprise.com> X-Deja-AN: 500687890 Content-Transfer-Encoding: 7bit References: <7mfs4t$g521@forums.borland.com> Organization: Inprise Corporation Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Newsgroups: borland.public.jbuilder.java.language