FlowLayout layout manager

Layout features

1. Locate the components line by line, from left to right in the line, and wrap when one line is full.
2. The default alignment is centered.
3. Without changing the size of the component, the component is displayed according to the original size of the component.
4. FlowLayout is the default layout manager for the Panel class.

explain

Different component spacing can be set in the construction method, and the line spacing is the alignment.

• JPanel panel=new JPanel(new FlowLayout(FlowLayout.RIGHT,20,40));

Right aligned, horizontal spacing between components is 20 pixels, and numerical spacing is 40 pixels

• JPanel panel=new JPanel(new FlowLayout(FlowLayout.LEFT));

Left aligned, horizontal and vertical spacing is the default (default) 5

• JPanel panel=new JPanel(new FlowLayout());

The default mode is centered alignment, and the horizontal and vertical spacing values are the default value of 5

Code display

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

public class TestFlowLayout extends JFrame {
    /**First define 8 buttons to test*/
    JButton[] jButtons=new JButton[8];
    /**There are many methods to define layout, and the most common method is shown here*/
    JPanel panel=new JPanel(new FlowLayout());
    public TestFlowLayout(){
        for (int i=0;i<jButtons.length;i++){
            jButtons[i]=new JButton("Button"+i);
            panel.add(jButtons[i]);
        }
        this.add(panel);
        this.setTitle("Streaming layout test");
        this.setSize(400,300);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        this.setVisible(true);
        }
       public static void main(String[] args){
        new TestFlowLayout();
       }
    }

  BorderLayout layout manager

Layout features

1. BorderLayout divides the whole container layout into five areas: Southeast, northwest, middle and middle. Component intelligence is added to the specified area.
2. If the adding part is not specified, it will be added to the Center area by default.
3. Only one can be added to each area. If more than one is added, the previous components will be abandoned.
4. BorderLayout is the default layout manager for the Frame class.

explain

  Code display

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

public class TestBorderLayout {

    public static void main(String[] args) {
        JFrame jf = new JFrame("BorderLayout Test management");
        jf.setSize(350, 250);
        jf.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        // Create a content container and specify a boundary layout to use
        JPanel panel = new JPanel(new java.awt.BorderLayout());
        JButton btnN = new JButton("North");
        JButton btnS = new JButton("South");
        JButton btnW = new JButton("West");
        JButton btnE = new JButton("East");
        JButton btnC = new JButton("Center");
        // Add the 5 buttons to the 5 directions in the container. Note that the following must be capitalized
        panel.add(btnN, java.awt.BorderLayout.NORTH);
        panel.add(btnS, java.awt.BorderLayout.SOUTH);
        panel.add(btnW, java.awt.BorderLayout.WEST);
        panel.add(btnE, java.awt.BorderLayout.EAST);
        panel.add(btnC, java.awt.BorderLayout.CENTER);
        jf.setContentPane(panel);
        jf.setLocationRelativeTo(null);
        jf.setVisible(true);
    }

}

GridLayout layout manager

Layout features

1. The GridLayout layout manager divides the layout into regular rectangular networks, and each cell area is the same size.
2. The component is added to each cell. Fill a row from left to right and wrap it from top to bottom.
3. Specify the number of rows and columns to split in the GridLayout constructor.

explain

  Code display

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

public class TestGridLayout extends JFrame {
    /**First define 8 buttons to test*/
    JButton[] jButtons=new JButton[8];
    /**There are many methods to define layout, and the most common method is shown here*/
    JPanel panel=new JPanel(new GridLayout(2,4));
    public TestGridLayout(){
        for (int i=0;i<jButtons.length;i++){
            jButtons[i]=new JButton("Button"+i);
            panel.add(jButtons[i]);
        }
        this.add(panel);
        this.setTitle("Table layout test");
        this.setSize(400,300);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        this.setVisible(true);
    }
    public static void main(String[] args){
        new TestGridLayout();
    }
}

Other layout management instructions

Layout name	explain	be careful
CardLayout	It can help users deal with two or more members sharing the same display space, just like a stack of cards stacked together.	Only one component can be displayed in a card, so you can use container nesting to display multiple components
GridBagLayout	The most flexible and complex layout manager, the space occupied by each component can be different and flexibly specified
Absolute layout	technological process: Object. setLocation (x,y); Object. setSize(80,80); (SetBounds can also be used to set four parameters at the same time) Container. setLayout(null)// Very important, otherwise you will find that your components will not display Container. Add (object);

Other layout code examples

CardLayout code

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class TestCardLayout {
    public static void main(String[] args) {
        JFrame jf = new JFrame("Card layout");
        jf.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        jf.setSize(300, 200);
        // Create a card layout with 10 horizontal and vertical spaces between cards
        final java.awt.CardLayout layout = new java.awt.CardLayout(10, 10);
        // Create a content panel container and specify a layout manager
        final JPanel panel = new JPanel(layout);
        JButton btn01 = new JButton("ha-ha");
        JButton btn02 = new JButton("hey");
        JButton btn03 = new JButton("Hoo hoo");
        panel.add(btn01, "btn01");
        panel.add(btn02, "btn02");
        panel.add(btn03, "btn03");
        // Show second first
        layout.show(panel, "btn02");
        jf.setContentPane(panel);
        jf.setLocationRelativeTo(null);
        jf.setVisible(true);
        // Switch to display the next one every 2 seconds
        new Timer(2000, new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                layout.next(panel);
            }
        }).start();
    }

}

 

GridBagLayout layout code

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

public class GridBagLayout {

    public static void main(String[] args) {
        JFrame jf = new JFrame("Test window");
        jf.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        java.awt.GridBagLayout gridBag = new java.awt.GridBagLayout();
        GridBagConstraints c = null;                    // constraint
        JPanel panel = new JPanel(gridBag);
        JButton btn01 = new JButton("1");
        JButton btn02 = new JButton("2");
        JButton btn03 = new JButton("3");
        JButton btn04 = new JButton("4");
        JButton btn05 = new JButton("5");
        JButton btn06 = new JButton("6");
        JButton btn07 = new JButton("7");
        JButton btn08 = new JButton("8");
        JButton btn09 = new JButton("9");
        JButton btn10 = new JButton("0");
        /* Add components and constraints to layout manager */
        // Button01
        c = new GridBagConstraints();
        gridBag.addLayoutComponent(btn01, c); // Only a copy of c is used internally
        // Button02
        c = new GridBagConstraints();
        gridBag.addLayoutComponent(btn02, c);
        // Button03
        c = new GridBagConstraints();
        gridBag.addLayoutComponent(btn03, c);
        // Button04 the display area occupies the remaining space of the current line (line feed), and the component fills the display area
        c = new GridBagConstraints();
        c.gridwidth = GridBagConstraints.REMAINDER;
        c.fill = GridBagConstraints.BOTH;
        gridBag.addLayoutComponent(btn04, c);
        // Button05 the display area has only one line (line feed), and the component fills the display area
        c = new GridBagConstraints();
        c.gridwidth = GridBagConstraints.REMAINDER;
        c.fill = GridBagConstraints.BOTH;
        gridBag.addLayoutComponent(btn05, c);
        // The Button06 display area occupies the second cell of the current component (manual line wrapping is required after the next component), and the component fills the display area
        c = new GridBagConstraints();
        c.gridwidth = GridBagConstraints.RELATIVE;
        c.fill = GridBagConstraints.BOTH;
        gridBag.addLayoutComponent(btn06, c);
        // Button07 is placed in the last cell of the current row (line feed)
        c = new GridBagConstraints();
        c.gridwidth = GridBagConstraints.REMAINDER;
        gridBag.addLayoutComponent(btn07, c);
        // The Button08 display area occupies two columns, and the component fills the display area
        c = new GridBagConstraints();
        c.gridheight = 2;
        c.fill = GridBagConstraints.BOTH;
        gridBag.addLayoutComponent(btn08, c);
        // The Button09 display area occupies the remaining space of the current line (line feed), and the component fills the display area
        c = new GridBagConstraints();
        c.gridwidth = GridBagConstraints.REMAINDER;
        c.fill = GridBagConstraints.BOTH;
        gridBag.addLayoutComponent(btn09, c);
        // The Button10 display area occupies the remaining space of the current line (line feed), and the component fills the display area
        c = new GridBagConstraints();
        c.gridwidth = GridBagConstraints.REMAINDER;
        c.fill = GridBagConstraints.BOTH;
        gridBag.addLayoutComponent(btn10, c);
        /* Add component to content panel */
        panel.add(btn01);
        panel.add(btn02);
        panel.add(btn03);
        panel.add(btn04);
        panel.add(btn05);
        panel.add(btn06);
        panel.add(btn07);
        panel.add(btn08);
        panel.add(btn09);
        panel.add(btn10);
        jf.setContentPane(panel);
        //Auto resize
        jf.pack();
        jf.setLocationRelativeTo(null);
        jf.setVisible(true);
    }

}