Thread: GridBagLayout can't seem to get it right.

Hello. I am trying to get some practice with Java GUI and using GridBagLayout.

I am trying to create a simple calculator applicatoin, and I am having problems getting the buttons just right. So in the code below, I've only made visible a handful of the buttons, but it illustrates the problem that I am having.

I want my calculator to look like the following:

textfield
1 2 3 +

where the buttons 1, 2, and 3 are of width 3, + is width 1, and textfield spans the entire width of the application.

The current code, when it displays, shows that buttons 1,2,3,+ all have the same wdith, yet I didn't specify that in the grid. Can someone find the problem in my code?

Maybe more importantly, should I be using GridBagLayout to do what I want? Or should I just take complete control of the layout?

thanks.

And now the code....


/* Calculator.java
*/


import java.awt.Container;
import java.awt.Component;
import java.awt.event.ActionListener;
import java.awt.Insets;
import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;

import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.BoxLayout;
import java.awt.BorderLayout;

class Calculator {
JFrame frame;
JTextField textfield;
JButton bt1, bt2, bt3, bt4, bt5, bt6, bt7, bt8, bt9, bt0;
JButton btDecimal, btEquals;
JButton btPlus, btMinus, btMultiply, btDivide;
final static Insets insets = new Insets(0,0,0,0);

public Calculator() {
frame = new JFrame( "Calculator");
frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE);
frame.setLayout( new GridBagLayout());

textfield = new JTextField(15);
bt1 = new JButton("1");
bt2 = new JButton("2");
bt3 = new JButton("3");
bt4 = new JButton("4");
bt5 = new JButton("5");
bt6 = new JButton("6");
bt7 = new JButton("7");
bt8 = new JButton("8");
bt9 = new JButton("9");
bt0 = new JButton("0");

btDecimal = new JButton( ".");
btEquals = new JButton( "=");

btPlus = new JButton( "+");
btMinus = new JButton( "-");
btMultiply = new JButton( "*");
btDivide = new JButton( "/");

addComponent( frame, textfield, 0,0, 10, 1);

addComponent( frame, bt1 , 0,1, 3, 1);
addComponent( frame, bt2 , 3,1, 3, 1);
addComponent( frame, bt3 , 6,1, 3, 1);
addComponent( frame, btPlus , 9,1, 1, 1);

frame.pack();
//frame.setSize(300,300);
frame.setVisible(true);
}

public void addComponent( Container container, Component component,
int gridx, int gridy, int widthx, int widthy)
{
GridBagConstraints gbc;
gbc = new GridBagConstraints
( gridx, gridy, widthx, widthy, 1.0, 1.0,
GridBagConstraints.CENTER,
GridBagConstraints.BOTH,
insets, 0, 0);

container.add( component, gbc);
return;
}
}


public class CalculatorEngine{
public static void main( String[] args) {
Calculator gui = new Calculator();
CalculatorEngine eng = new CalculatorEngine();

return;
}
}

Sorry about that very first post. Again I am trying to make a calculator and I want the numbers to be fatter buttons than the operators like '+'. However, the GridBagLayout Manager always seems to want to resize the buttons to be the same size.

So below is much shortened version of the problem code. Notice that when I addComponent(), I specify that the size of the number pads should be 3 times the width of the plus button. But when you run this code, you'll see that the buttons arre all the same width.

Any suggestions? Thanks.

/* CalculatorEngine.java
 */
 
 
import java.awt.Container;
import java.awt.Component;
import java.awt.event.ActionListener;
import java.awt.Insets;
import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;
 
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.BoxLayout;
import java.awt.BorderLayout;
 
class Calculator {
    JFrame frame;
    JTextField textfield;
    JButton bt1, bt2, bt3;
    JButton btPlus;
 
    final static Insets insets = new Insets(0,0,0,0);
 
    public Calculator() {
	frame = new JFrame( "Calculator");
	frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE);
	frame.setLayout( new GridBagLayout());
 
	textfield = new JTextField(15);
	bt1 = new JButton("1");
	bt2 = new JButton("2");
	bt3 = new JButton("3");
	btPlus = new JButton( "+");
 
	addComponent( frame, textfield, 0,0, 10, 1);
 
	addComponent( frame, bt1      , 0,1, 3,  1);
	addComponent( frame, bt2      , 3,1, 3,  1);
	addComponent( frame, bt3      , 6,1, 3,  1);
	addComponent( frame, btPlus   , 9,1, 1,  1);
 
	frame.pack();
	//frame.setSize(300,300);
	frame.setVisible(true);
    }
 
    public void addComponent( Container container, Component component, 
			      int gridx, int gridy, int widthx, int widthy)
    {
	GridBagConstraints gbc;
	gbc = new GridBagConstraints
	    ( gridx, gridy, widthx, widthy, 1.0, 1.0,
	      GridBagConstraints.CENTER,
	      GridBagConstraints.BOTH,
	      insets, 0, 0);
 
	container.add( component, gbc);
	return;
    }
}
 
 
public class CalculatorEngine{
    public static void main( String[] args) {
	Calculator gui = new Calculator();
	CalculatorEngine eng = new CalculatorEngine();
 
	return;
    }
}