GridBagLayout Question???

Question

I am new to Java and I am trying to create a window with the fhe fields starting at gridx=0 and gridy=0 but I get the fields centered in the middle of the window. Is there a problem with my code????
Thanks
Ralph
import javax.swing.*;
import java.awt.*;
public class SwingWindow extends JFrame
private GridBagLayout layout;
private GridBagConstraints constraints;
private Container container;
// setup GUI
public SwingWindow()
super("Java Test Window");
container = getContentPane();
layout = new GridBagLayout();
container.setLayout( layout );
// instantiate gridbag contraints
constraints = new GridBagConstraints();
// create GUI Components
JLabel textLabel = new JLabel("Name : ");
JTextField text = new JTextField("",15);
JLabel textLabel2 = new JLabel("Address : ");
JTextField text2 = new JTextField("",15);
// define GUI Component constraints for Textlabel
constraints.gridwidth = 1;
constraints.gridheight = 1;
constraints.gridx = 0;
constraints.gridy = 0;
constraints.fill = GridBagConstraints.BOTH;
addComponent(textLabel);
// define GUI Component constraints for TextField
constraints.gridwidth = 1;
constraints.gridheight = 1;
constraints.gridx = 1;
constraints.gridy = 0;
constraints.fill = GridBagConstraints.BOTH;
addComponent(text);
// define GUI Component constraints for Textlabel2
constraints.gridwidth = 1;
constraints.gridx = 0;
constraints.gridy = 1;
constraints.fill = GridBagConstraints.BOTH;
addComponent(textLabel2);
// define GUI Component constraints for TextField2
constraints.gridwidth = 1;
constraints.gridx = 1;
constraints.gridy = 1;
constraints.fill = GridBagConstraints.BOTH;
addComponent(text2);
setSize( 500, 400);
setVisible( true );
} //end constructor
//add a components to the container
private void addComponent( Component component)
layout.setConstraints( component, constraints);
container.add( component );
public static void main(String args [] )
SwingWindow application = new SwingWindow();
application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
} // End of SwingWindow

Answer 1

Ever hear the expression "Don't try this at home"?
The GridBagLayout is the most powerful and also the most confusing and frustrating layout manager you can use. It's powerful because you can do almost anything with it. It is confusing and frustrating because one little oopsie can send the whole house of cards tumbling down.
You should only use it if you either
are very experienced with layout managers in general
or
are willing to do a lot of research and experimentation.
In your case the problem is caused by one leeeeeetle omission; you forgot to assign weights to the components; all of your constraints have a weight of 0 (although why this completely blows your orientation is still a mystery to me).
Try thisimport javax.swing.*;
import java.awt.*;
public class LayoutDemo extends JFrame
  private GridBagLayout layout;
  private GridBagConstraints constraints;
  private Container container;
  // setup GUI
  public LayoutDemo()
    super ("Java Test Window");
    setSize (500, 400);
    container = getContentPane();
    layout = new GridBagLayout();
    container.setLayout (layout);
    // instantiate gridbag constraints
    constraints = new GridBagConstraints();
    // create GUI Components
    JLabel textLabel = new JLabel ("Name : ");
    JTextField text = new JTextField ("",15);
    JLabel textLabel2 = new JLabel ("Address : ");
    JTextField text2 = new JTextField ("",15);
    // Define global constraints all components
    constraints.gridwidth = 1;
    constraints.gridheight = 1;
    constraints.weightx = 0;
    constraints.weighty = 0;
    constraints.anchor = GridBagConstraints.NORTHWEST;
    constraints.fill = GridBagConstraints.NONE;
    constraints.insets = new Insets (3, 3, 3, 3); // Leave some space between controls
    // define specific constraints for Textlabel
    constraints.gridx = 0;
    constraints.gridy = 0;
    addComponent (textLabel);
    // define GUI Component constraints for Textlabel2
    constraints.gridx = 0;
    constraints.gridy = 1;
    constraints.weighty = 1.0;
    addComponent (textLabel2);
    // define GUI Component constraints for TextField
    constraints.gridx = 1;
    constraints.gridy = 0;
    constraints.weightx = 1.0;
    constraints.weighty = 0;
    constraints.fill = GridBagConstraints.HORIZONTAL;
    addComponent (text);
    // define GUI Component constraints for TextField2
    constraints.gridx = 1;
    constraints.gridy = 1;
    constraints.weighty = 1.0;
    addComponent (text2);
    setVisible (true );
    return;
    // Enumerate the components with their constraints (debug only)
    Component[] allControls = container.getComponents();
    for (int i = 0; i < allControls.length; ++i)
      GridBagConstraints currentConstraints = layout.getConstraints (allControls );
System.out.println ("x/y = " +
currentConstraints.gridx + ", " +
currentConstraints.gridy +
"; w/h = " +
currentConstraints.gridwidth + ", " +
currentConstraints.gridheight);
} //end constructor
//add a components to the container
private void addComponent( Component component)
layout.setConstraints( component, constraints);
container.add( component );
public static void main (String args [])
JFrame application = new LayoutDemo();
application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
} // End of SwingWindow