如何使用GridBagLayout和GridLayout进行最佳对齐？

Question

I wanted to try out GridBagLayout in my program but sadly I don't clearly understand it, I tried implementing GridLayout also but both give me different problems. Let me show you the code and the output picture to further clarify it:

package iKleen;

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

public class ikleenRegister {

    JFrame frame;
    JPanel phonePanel, fieldPanel, mainPanel;
    JLabel name, email, password, address, mobile, l_register;
    JTextField nameField, emailField, passwordField, addressField, mobileField, countryCode;
    JButton b_register;
    GridBagConstraints c;

    public void launchGUI()
    {
        frame = new JFrame("iKleen - Register / Create Free Account");

        //phonePanel and its components
        phonePanel = new JPanel();
        phonePanel.setLayout(new FlowLayout(FlowLayout.CENTER, 0, 0));
        mobileField = new JTextField(8);
        countryCode = new JTextField(2);
        countryCode.setText("+91");
        countryCode.setEnabled(false);
        phonePanel.add(countryCode);
        phonePanel.add(mobileField);

        //fieldPanel and its components
        fieldPanel = new JPanel();
        fieldPanel.setLayout(new GridBagLayout());
        fieldPanel.setBorder(BorderFactory.createEmptyBorder(25,25,25,25));
        c = new GridBagConstraints();
        c.fill = GridBagConstraints.HORIZONTAL;
        name = new JLabel("Name: ");
        email = new JLabel("Email ID: ");
        password = new JLabel("Password: ");
        address = new JLabel("Address: ");
        mobile = new JLabel("Mobile Number: ");
        nameField = new JTextField(15);
        emailField = new JTextField(15);
        passwordField = new JTextField(15);
        addressField = new JTextField(20);
        c.gridx=0;
        c.gridy=0;
        fieldPanel.add(name, c);
        c.gridx=1;
        c.gridy=0;
        fieldPanel.add(nameField, c); 
        c.gridx=0;
        c.gridy=1;
        fieldPanel.add(email, c);
        c.gridx=1;
        c.gridy=1;
        fieldPanel.add(emailField, c);
        c.gridx=0;
        c.gridy=2;
        fieldPanel.add(password, c);
        c.gridx=1;
        c.gridy=2;
        fieldPanel.add(passwordField, c);
        c.gridx=0;
        c.gridy=3;
        fieldPanel.add(address, c);
        c.gridx=1;
        c.gridy=3;
        fieldPanel.add(addressField, c);
        c.gridx=0;
        c.gridy=4;
        fieldPanel.add(mobile, c);
        c.gridx=1;
        c.gridy=4;
        fieldPanel.add(phonePanel, c);

        //mainPanel and its components
        mainPanel = new JPanel();
        mainPanel.setBorder(BorderFactory.createEmptyBorder(25,25,25,25));
        mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));
        Font font = new Font("MS Sans Serif", Font.BOLD, 18);
        l_register = new JLabel("Create a free account");
        l_register.setFont(font);
        l_register.setAlignmentX(Component.CENTER_ALIGNMENT);
        b_register = new JButton("Create Account");
        b_register.setAlignmentX(Component.CENTER_ALIGNMENT);
        mainPanel.add(l_register);
        mainPanel.add(fieldPanel);
        mainPanel.add(b_register);

        //final frame settings
        frame.setContentPane(mainPanel);
        frame.pack();
        centerFrame();
        frame.setVisible(true);
        frame.setResizable(false);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public void centerFrame() {
        Dimension currentScreen = Toolkit.getDefaultToolkit().getScreenSize();
        int x = (int) ((currentScreen.getWidth() - frame.getWidth()) / 2);
        int y = (int) ((currentScreen.getHeight() - frame.getHeight()) / 2);
        frame.setLocation(x, y);
    }
}

OUTPUT: gridbaglayout

package iKleen;

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

public class ikleenRegister {

    JFrame frame;
    JPanel phonePanel, fieldPanel, mainPanel;
    JLabel name, email, password, address, mobile, l_register;
    JTextField nameField, emailField, passwordField, addressField, mobileField, countryCode;
    JButton b_register;

    public void launchGUI()
    {
        frame = new JFrame("iKleen - Register / Create Free Account");

        //phonePanel and its components
        phonePanel = new JPanel();
        phonePanel.setLayout(new FlowLayout(FlowLayout.CENTER, 0, 0));
        mobileField = new JTextField(15);
        countryCode = new JTextField(2);
        countryCode.setText("+91");
        countryCode.setEnabled(false);
        phonePanel.add(countryCode);
        phonePanel.add(mobileField);

        //fieldPanel and its components
        fieldPanel = new JPanel();
        fieldPanel.setLayout(new GridLayout(5,2,3,3));
        fieldPanel.setBorder(BorderFactory.createEmptyBorder(25,25,25,25));
        name = new JLabel("Name: ");
        email = new JLabel("Email ID: ");
        password = new JLabel("Password: ");
        address = new JLabel("Address: ");
        mobile = new JLabel("Mobile Number: ");
        nameField = new JTextField(15);
        emailField = new JTextField(15);
        passwordField = new JTextField(15);
        addressField = new JTextField(15);
        fieldPanel.add(name);
        fieldPanel.add(nameField);
        fieldPanel.add(email);
        fieldPanel.add(emailField);
        fieldPanel.add(password);
        fieldPanel.add(passwordField);
        fieldPanel.add(address);
        fieldPanel.add(addressField);
        fieldPanel.add(mobile);
        fieldPanel.add(phonePanel);

        //mainPanel and its components
        mainPanel = new JPanel();
        mainPanel.setBorder(BorderFactory.createEmptyBorder(25,25,25,25));
        mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));
        Font font = new Font("MS Sans Serif", Font.BOLD, 18);
        l_register = new JLabel("Create a free account");
        l_register.setFont(font);
        l_register.setAlignmentX(Component.CENTER_ALIGNMENT);
        b_register = new JButton("Create Account");
        b_register.setAlignmentX(Component.CENTER_ALIGNMENT);
        mainPanel.add(l_register);
        mainPanel.add(fieldPanel);
        mainPanel.add(b_register);

        //final frame settings
        frame.setContentPane(mainPanel);
        frame.pack();
        centerFrame();
        frame.setVisible(true);
        frame.setResizable(false);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public void centerFrame() {
        Dimension currentScreen = Toolkit.getDefaultToolkit().getScreenSize();
        int x = (int) ((currentScreen.getWidth() - frame.getWidth()) / 2);
        int y = (int) ((currentScreen.getHeight() - frame.getHeight()) / 2);
        frame.setLocation(x, y);
    }
}

OUTPUT: gridlayout

In the gridbaglayout, the number field is not aligned with the rest of the fields, I want them to align at their start point just like the jlabels. And in the gridlayout, their is too much gap between the jfields and the jlabels, I tried many solutions, sadly to no avail.

Answer 1

For the GridLayout:

The "gap" you see between the jlabels and jtextfield is caused by the fact that, in GridLayout, every cell has exactly the same width and height. Hence, since your jtextfields are wider than the labels, they will become wider to fit their cells.

So, if you still want to use a GridLayout without that gap you could:

• Try to restrict your jtextfields, given a different number of columns to the constructor (currently max is 20).
• Align your jlabels to the right. This will cause the empty gap to be placed on the left of the labels.

Of course those are not solutions, they are a sort of compromises, since your panel will change aspect.

I suggest you to use a GridBagLayout, changing your "phonePanel" layout. If you don't care your phonePanel to have the same width of the other textfields, you can use a flowlayout with left alignment :

phonePanel.setLayout (new FlowLayout(FlowLayout.LEFT, 0, 0));

You will have this result:

If you prefer to have the same width, you could set a BorderLayout to your phonePanel, adding the country code on BorderLayout.WEST (to give it a fixed size) and adding mobileField at the center (to let it taking all the extra space).

phonePanel.setLayout(new BorderLayout());
phonePanel.add(countryCode, BorderLayout.WEST);
phonePanel.add(mobileField, BorderLayout.CENTER); 

This is the result:

Finally, you can use insets to insert a little gap between labels and textfields.

Answer 2

Your both tries (with GridBagLayout and GridLayout for the outer panel) were quite close to a solution. The problem was the FlowLayout of your phonePanel . In both variants you can solve the issue by replacing it with a BorderLayout (with zero gaps):

    //phonePanel and its components
    phonePanel = new JPanel();
    phonePanel.setLayout(new BorderLayout(0, 0));
    mobileField = new JTextField(15);
    countryCode = new JTextField(2);
    countryCode.setText("+91");
    countryCode.setEnabled(false);
    phonePanel.add(countryCode, BorderLayout.WEST);
    phonePanel.add(mobileField, BorderLayout.CENTER);

For your GridLayout variant, do the above fix:

For your GridBagLayout variant, do the above fix.
And for a nicer look you can introduce some padding around your components by:

c.insets = new Insets(5, 10, 5, 10);  // top, left, bottom, right padding

Answer 3

For GridBagLayout, update the following line of code. You are using FlowLayout.CENTER which moves the mobile number field to middle of panel.

phonePanel.setLayout(new FlowLayout(FlowLayout.LEFT, 0, 0));