GridBagLayout

Hello!

Having some odd issues using a GridBagLayout, where I have components in odd places, or on top of other components.

Any suggestions would be brilliant. :]

Code:

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public void addComponent(Container contentPane){
            setContentPane(contentPane);
            GridBagConstraints c = new GridBagConstraints();
            contentPane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
           
            //display = new JTextArea("k");
            //display.setSize(FRAME_WIDTH, FRAME_HEIGHT / 2);
            //display.setVisible(true);
            //c.fill = GridBagConstraints.HORIZONTAL;
            //c.gridx = 0;
            //c.gridy = 0;
            //c.gridwidth = 3;
           
           
            loanAmountLabel = new JLabel("Loan Amount");
            c.fill = GridBagConstraints.HORIZONTAL;
            c.insets = new Insets(10, 10, 10, 10);
            c.gridx = 0;
            c.gridy = 1;
            c.gridwidth = 1;
            contentPane.add(loanAmountLabel, c);
           
            interestRateLabel = new JLabel("Interest Rate");
            c.fill = GridBagConstraints.HORIZONTAL;
            c.gridx = 1;
            c.gridy = 1;
            c.gridwidth = 1;
            contentPane.add(interestRateLabel, c);
           
            loanPeriodLabel = new JLabel("Loan Period");
            c.fill = GridBagConstraints.HORIZONTAL;
            c.gridx = GridBagConstraints.RELATIVE;
            c.gridy = 2;
            c.gridwidth = 1;
            contentPane.add(loanPeriodLabel, c);
           
            loanAmount = new JTextField();
            c.fill = GridBagConstraints.HORIZONTAL;
            c.gridx = 0;
            c.gridy = 2;
            c.gridwidth = 1;
            contentPane.add(loanAmount, c);
           
            interestRate = new JTextField();
            c.fill = GridBagConstraints.HORIZONTAL;
            c.gridx = 1;
            c.gridy = 2;
            c.gridwidth = 1;
            contentPane.add(interestRate, c);
           
            loanPeriod = new JTextField();
            c.fill = GridBagConstraints.HORIZONTAL;
            c.gridx = 2;
            c.gridy = 2;
            c.gridwidth = 1;
            contentPane.add(loanPeriod, c);
    }

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Moved from New to Java.

Nowhere in the posted code is the layout set to a GridBagLayout. To get better help sooner, post a SSCCE (Short, Self Contained, Correct (Compilable), Example) that demonstrates the problem.

db

Thanks for the tip. This one should be compilable.

Code:

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package mortgagecalc;

import java.awt.ComponentOrientation;
import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.LayoutManager;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.*;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class MortgageCalc extends JFrame implements ActionListener{
       
        JTextField loanAmount, interestRate, loanPeriod;
        JLabel loanAmountLabel, interestRateLabel, loanPeriodLabel;

        public static void main( String[] args ) {
                MortgageCalc frame = new MortgageCalc();
                frame.setVisible(true);
        }

        public MortgageCalc(){
                setSize(FRAME_WIDTH, FRAME_HEIGHT);
                setResizable(false);
                setDefaultCloseOperation(EXIT_ON_CLOSE);
                setLocationRelativeTo(null);
                JPanel content = new JPanel(new GridBagLayout());
                addComponent(content);
        }

public void addComponent(Container contentPane){
            setContentPane(contentPane);
            GridBagConstraints c = new GridBagConstraints();
            contentPane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
           
            //display = new JTextArea("k");
            //display.setSize(FRAME_WIDTH, FRAME_HEIGHT / 2);
            //display.setVisible(true);
            //c.fill = GridBagConstraints.HORIZONTAL;
            //c.gridx = 0;
            //c.gridy = 0;
            //c.gridwidth = 3;
           
           
            loanAmountLabel = new JLabel("Loan Amount");
            c.fill = GridBagConstraints.HORIZONTAL;
            c.insets = new Insets(10, 10, 10, 10);
            c.gridx = 0;
            c.gridy = 1;
            c.gridwidth = 1;
            contentPane.add(loanAmountLabel, c);
           
            interestRateLabel = new JLabel("Interest Rate");
            c.fill = GridBagConstraints.HORIZONTAL;
            c.gridx = 1;
            c.gridy = 1;
            c.gridwidth = 1;
            contentPane.add(interestRateLabel, c);
           
            loanPeriodLabel = new JLabel("Loan Period");
            c.fill = GridBagConstraints.HORIZONTAL;
            c.gridx = GridBagConstraints.RELATIVE;
            c.gridy = 2;
            c.gridwidth = 1;
            contentPane.add(loanPeriodLabel, c);
           
            loanAmount = new JTextField();
            c.fill = GridBagConstraints.HORIZONTAL;
            c.gridx = 0;
            c.gridy = 2;
            c.gridwidth = 1;
            contentPane.add(loanAmount, c);
           
            interestRate = new JTextField();
            c.fill = GridBagConstraints.HORIZONTAL;
            c.gridx = 1;
            c.gridy = 2;
            c.gridwidth = 1;
            contentPane.add(interestRate, c);
           
            loanPeriod = new JTextField();
            c.fill = GridBagConstraints.HORIZONTAL;
            c.gridx = 2;
            c.gridy = 2;
            c.gridwidth = 1;
            contentPane.add(loanPeriod, c);
    }

        @Override
        public void actionPerformed(ActionEvent arg0) {
                // TODO Auto-generated method stub
               
        }
}

---

Quote:

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Originally Posted by Razion

Thanks for the tip. This one should be compilable.

---

Nope.

Code:

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E:\Java\examples\src\swing\layout\MortgageCalc.java:17: cannot find symbol
symbol  : variable FRAME_WIDTH
location: class swing.layout.MortgageCalc
            setSize(FRAME_WIDTH, FRAME_HEIGHT);
E:\Java\examples\src\swing\layout\MortgageCalc.java:17: cannot find symbol
symbol  : variable FRAME_HEIGHT
location: class swing.layout.MortgageCalc
            setSize(FRAME_WIDTH, FRAME_HEIGHT);
2 errors

---

db

After fixing that, the code does pretty much what I would expect.

-- The JTextFields are constructed using the no-arg constructor, so the preferredSize.width is a few pixels.
-- Those text fields that are in the same column as a JLabel adopt the preferred width of the label
-- loanPeriodLabel is added with x=RELATIVE, which evaluates to 2 (relative to 1 for interestRateLabel) and y=2, so occupies the same cell as loanPeriod

A note: posting several commented lines only adds clutter, as does an empty implemention of an interfacethat has nothing to do with your question. You should take the trouble to remove them when posting on a forum. Also, there's no point repeatedly assigning the same value to the same field of your GridBagConstraints. Here's your code correctly formatted/indented and with all redundant lines removed; no other changes, except to change the fields to local variables (this is a layout problem; they aren't needed at the class level) and launch the GUI on the EDT (see Lesson: Concurrency in Swing (The Java™ Tutorials > Creating a GUI With JFC/Swing)).

Notice how much shorter it is.

Code:

---

import java.awt.*;
import javax.swing.*;

public class MortgageCalc extends JFrame {

  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {

      @Override
      public void run() {
        new MortgageCalc().setVisible(true);
      }
    });
  }

  public MortgageCalc() {
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    JPanel content = new JPanel(new GridBagLayout());
    addComponent(content);
    pack();
    setLocationRelativeTo(null);
  }

  public void addComponent(Container contentPane) {
    setContentPane(contentPane);
    GridBagConstraints c = new GridBagConstraints();
    contentPane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);

    JLabel loanAmountLabel = new JLabel("Loan Amount");
    c.fill = GridBagConstraints.HORIZONTAL;
    c.insets = new Insets(10, 10, 10, 10);
    c.gridx = 0;
    c.gridy = 1;
    contentPane.add(loanAmountLabel, c);

    JLabel interestRateLabel = new JLabel("Interest Rate");
    c.gridx = 1;
    contentPane.add(interestRateLabel, c);

    JLabel loanPeriodLabel = new JLabel("Loan Period");
    c.gridx = GridBagConstraints.RELATIVE;
    c.gridy = 2;
    contentPane.add(loanPeriodLabel, c);

    JTextField loanAmount = new JTextField();
    c.gridx = 0;
    contentPane.add(loanAmount, c);

    JTextField interestRate = new JTextField();
    c.gridx = 1;
    contentPane.add(interestRate, c);

    JTextField loanPeriod = new JTextField();
    c.gridx = 2;
    contentPane.add(loanPeriod, c);
  }
}

---

db