Re: JFrame window dimensions
On 2010-07-11 15:35 John B. Matthews wrote:
In article <i1csh7$tgb$1@news.albasani.net>, Lew <noone@lewscanon.com>
wrote:
John B. Matthews wrote:
As suggested previously, don't neglect to build your GUI on the EDT.
...
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new Temp();
}
});
}
And don't run the GUI from the constructor.
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new Temp().setVisible(true);
}
});
}
Lew: Ah, a subtle trap for the unwary. Thanks for highlighting it. IIUC,
this is predicated on the idea that the constructor should complete
before invoking the instance's public methods.
Eustace: More on the recommended approach is shown in the "Initial
Threads" section of the tutorial [1]. Here's another idiom that avoids
the peril and obviates extending JFrame. Also, I've found it instructive
to run the program in a profiler while resizing the window, paying
particular attention to the event queue.
import java.awt.*;
import javax.swing.*;
/** @author John B. Matthews */
public class Temp implements Runnable {
private static final int B = 10; // border
public static void main(String[] args) {
EventQueue.invokeLater(new Temp());
}
@Override
public void run() {
JFrame frame = new JFrame("Temp");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel(new GridLayout());
panel.setBorder(BorderFactory.createEmptyBorder(B, B, B, B));
panel.add(new CustomPanel());
frame.add(panel);
frame.pack(); // adjust to the preferred size of subcomponents.
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private static final class CustomPanel extends JPanel {
private static final int W = 1200;
private static final int H = 600;
public CustomPanel() {
this.setPreferredSize(new Dimension(W, H));
this.setBackground(Color.black);
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
System.out.println(getWidth() + " " + getHeight());
}
}
}
[1]<http://download.oracle.com/docs/cd/E17409_01/javase/tutorial/uiswing/
concurrency/initial.html>
Thanks for your replies. It was only reasonable that it had to be an
automatic way to make the dimensions of the window the desired ones.
The border was not the main issue in my original posting. I could just
as well have drawn any rectangle equidistant to the sides of the window
to make my point, or a circle inscribed in it.
In my program I follow an example of the book "Java In Easy Steps"
(Painting application fonts and colors, p.150-1). This is by far the
shortest of the 3 books I studied learning Java, (keeping the programs -
exercises in them handy to consult in the future when necessary as a
first source of help,) and yet I find it the most helpful for quick
answers. One of the others was for preparation for the certification
exam, and it included topics like Threads and Streams, things that I did
not expect to need any time soon. However, I do not remember
encountering "EventQueue.invokeLater()" or "@Override" there. I would
prefer to solve the problem without using things I do not yet
understand, it seems, however, I have to follow your approach above to
do so.
Thanks again,
emf
--
It ain't THAT, babe! - A radical reinterpretation
https://files.nyu.edu/emf202/public/bd/itaintmebabe.html