GUI: how to properly set layout

问题:

I'm having some issues with setting layouts. (Don't mind the sizes of the buttons, I just want to understand layouts properly).

Here is the window that I want to make:

Here is the window I tried:

Here's my code:

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

class Grid extends JFrame
{
    private JTextField t1;
    private JTextField t2;
    private JCheckBox c1;
    private JCheckBox c2;
    private JButton b1;
    private JButton b2;
    private JButton b3;
    private JPanel ButtonPanel1;
    private JPanel ButtonPanel2;
    private JPanel ButtonPanel3;
    private JPanel CheckPanel1;
    private JPanel CheckPanel2;
    private JPanel TextPanel1;
    private JPanel TextPanel2;
    private JPanel EastPanel;
    private JPanel CenterPanel;
    private JPanel WestPanel;
    private JLabel l1;
    private JLabel l2;

    public Grid()
    {
        //CheckBoxes
         c1 = new JCheckBox("Snap to Grid");
         c2 = new JCheckBox("Show Grid");

         CheckPanel1 = new JPanel();
         CheckPanel1.add(c1);

         CheckPanel2 = new JPanel();
         CheckPanel2.add(c2);
         WestPanel = new JPanel(new GridLayout(2,1));
         WestPanel.add(c1);
         WestPanel.add(c2);
         add(WestPanel,BorderLayout.WEST);

          //I don't get how to arrange the labels aligned with the textfields. 

         //TextFields
         l1 = new JLabel("X:");
         t1 = new JTextField("8",3);
         l2 = new JLabel("Y:");
         t2 = new JTextField("8",3);

         TextPanel1 = new JPanel();
         TextPanel1.add(l1);
         TextPanel1.add(t1);

         TextPanel2 = new JPanel();
         TextPanel2.add(l2);
         TextPanel2.add(t2);

         CenterPanel = new JPanel(new GridLayout(2,1));
         CenterPanel.add(l1);
         CenterPanel.add(l2);
         CenterPanel.add(t1);
         CenterPanel.add(t2);
         add(CenterPanel,BorderLayout.CENTER); 

         // Buttons
         b1 = new JButton("Ok");
         b2 = new JButton("Cancel");
         b3 = new JButton("Help");

         ButtonPanel1 = new JPanel();
         ButtonPanel1.add(b1);

         ButtonPanel2 = new JPanel();
         ButtonPanel2.add(b2);

         ButtonPanel3 = new JPanel();
         ButtonPanel3.add(b3);

         EastPanel = new JPanel(new GridLayout(3,1));
         EastPanel.add(ButtonPanel1);
         EastPanel.add(ButtonPanel2);
         EastPanel.add(ButtonPanel3);

         add(EastPanel, BorderLayout.EAST);

    }
}

public class oottest {

    public static void main(String[] args) {

        Grid app = new Grid();

        app.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        app.setSize(300,150);
        app.setVisible(true);
    }

}

Can anyone help me understand how layout works?

I have been watching lots of videos and tried different layouts but still can't get it right. Tell me if I used the correct layout or if I should change it.

回答1:

GridBagLayout as proposed in this answer can give all the control you need for the left part.
If you are willing to sacrifice some control for the sake of simplicity, you can get away with two FlowLayout panels inside a GridLayout:

import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

class Grid extends JFrame
{
    private JTextField t1, t2;
    private JCheckBox c1, c2;
    private JButton b1, b2, b3;
    private JPanel topPanel, bottomPanel;
    private JPanel eastPanel, centerPanel;
    private JLabel l1, l2;

    public Grid()
    {
         c1 = new JCheckBox("Snap to Grid");
         l1 = new JLabel("X:");
         t1 = new JTextField("8",3);

         topPanel = new JPanel();//uses flow layout by default
         topPanel.add(c1); topPanel.add(l1); topPanel.add(t1);

         c2 = new JCheckBox("Show Grid");
         l2 = new JLabel("Y:");
         t2 = new JTextField("8",3);

         bottomPanel = new JPanel();
         bottomPanel.add(c2);  bottomPanel.add(l2); bottomPanel.add(t2);

         centerPanel = new JPanel(new GridLayout(2,1));
         centerPanel.add(topPanel);
         centerPanel.add(bottomPanel);
         add(centerPanel,BorderLayout.CENTER);

         b1 = new JButton("Ok");
         b2 = new JButton("Cancel");
         b3 = new JButton("Help");

         eastPanel = new JPanel(new GridLayout(3,1));
         eastPanel.add(b1);
         eastPanel.add(b2);
         eastPanel.add(b3);
         add(eastPanel, BorderLayout.EAST);
    }

    public static void main(String[] args) {

        Grid app = new Grid();
        app.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        app.setSize(300,150);
        app.setVisible(true);
    }
}

回答2:

I'd use a single column GridLayout for the buttons on the right, a GridBagLayout for everything to the left of them. Put the panel with the buttons in the LINE_END of a BorderLayout and the rest in the CENTER.

Here is how it might look:

Adjust margins, layout padding, insets and empty border for required white space. (Batteries not included.)