Beginner Java problem

[ConMan318]

I have just begun learning Java and I typed this code:


import javax.swing.*;

public class TestJava {
public static void main(String[] args) {
JFrame frame = new JFrame("Hello, Java!");
JLabel label = new JLabel("Hello, Java!", JLabel.CENTER);
frame.getContentPane().add(label);
frame.setSize(300, 300);
frame.setVisible(true);
}
}

Upon compiling, this error is generated:


connor@connor-laptop:~/Documents/programs/java$ javac TestJava.java
TestJava.java:6: warning: The static field SwingConstants.CENTER should be accessed directly
JLabel label = new JLabel("Hello, Java!", JLabel.CENTER);
^^^^^^
1 problem (1 warning)

It still runs the program, except when the window opens it doesn't close, then it grays out and I have to force a quit. I'm not sure if this problem is related to the error or not.

But how can I access the static field SwingConstants directly?

[drubin]

SwingConstants.CENTER

also there is an option something like

JFrame.setDefaultCloseOption(JFrame.EXIT_ON_CLOSE)

I could be wrong about the exact parameters but think the function is right.

[mike_g]

Yeah, its more like:


frame.setDefaultCloseOperation(WindowConstants.EXI T_ON_CLOSE);

By in my experience that has always already been set somewhere. Dunno, maybe Netbeans did it automatically for me.

I'm not sure if youre going about centering the text in the JLabel correctly; or at least I have never done it that way. This should work:

JLabel label = new JLabel("Hello, Java!");
label.setHorizontalAlignment(SwingConstants.CENTER );

[drubin]

Yeah, its more like:


frame.setDefaultCloseOperation(WindowConstants.EXI T_ON_CLOSE);

By in my experience that has always already been set somewhere. Dunno, maybe Netbeans did it automatically for me.


The fact I wrote JFrame.EXIT_ON_CLOSE is still valid as Source code for JFrame is

JFrame ..... implements WindowConstants (Some where up the component tree.)

Also im my experience if your idea is doing some thing to your code with out your knowledge you might want to check it out? :) as this is not the default behavior of a base JFrame.

The default behavior is.
JFrame.DO_NOTHING_ON_CLOSE;

[mike_g]

Well, I did say that I use netbeans, and like I said it seems to set the default close operation to exit by default. Also, the code you originally posted wouldent work for me, probably cos you wrote its as setDefaultCloseOption.

[drubin]

probably cos you wrote its as setDefaultCloseOption.

:) sorry was a late, night.