Introduction to GUI programming to game practice (I)

GUI Introduction to programming to game practice （ One ）

GUI It's the graphical user interface , It's a graphical interface ,windows Is a graphical user interface operating system , and DOS Is a command prompt based operating system ,GUI Programming is Program a graphical user interface software .

Components ：

• window
• Popup
• panel
• The text box
• List box
• Button
• picture
• Monitoring events
• mouse
• Keyboard events
• Crack tools

1. brief introduction

GUI Two core programming techniques of :Swing AWT

• The interface is not beautiful
• need jre Environmental Science

therefore , It didn't catch on .

Why study ？

• You can write about the small public actions you want
• Maintenance may be required during operation swing Interface （ The probability is small ）
• understand MVC framework , Learn about monitoring

AWT It's the ground floor ,Swing It's encapsulated

2.AWT

2.1AWT Introduce

1） Contains many classes and interfaces , be used for GUI（ Graphical user interface ） Programming

2） Elements ： window 、 Button 、 The text box

3）java.awt

2.2 Components and containers

1.Frame window

package com.song.lesson01;

import java.awt.*;

//GUI The first interface of 
public class TestFrame {
    
    public static void main(String[] args) {
    

        //Frame JDK  Look at the source code 
        Frame frame = new Frame(" My first one Java Image interface window ");

        // You need to set visibility 
        frame.setVisible(true);

        // Set window size 
        frame.setSize(400,400);

        // Set the background color  Color
        //frame.setBackground(Color.black);// Direct use 
        frame.setBackground(new Color(85,150,68));// own new One , Set up RGB Value 

        // The initial position of the pop-up 
        frame.setLocation(200,200);// Screen coordinates （0,0） spot , In the upper left corner 

        // Set the size fixed 
        frame.setResizable(false);// Can't change 
    }
}

Operation result diagram ：

Try to encapsulate ：

package com.song.lesson01;

import java.awt.*;

public class TestFrame2 {
    
    public static void main(String[] args) {
    
        // Show multiple windows 
        // Make a package inheritance 
        MyFrame myFrame01 = new MyFrame(100, 100, 200, 200, Color.blue);
        MyFrame myFrame02 = new MyFrame(300, 100, 200, 200, Color.yellow);
        MyFrame myFrame03 = new MyFrame(100, 300, 200, 200, Color.pink);
        MyFrame myFrame04 = new MyFrame(300, 300, 200, 200, Color.green);

    }
}

class MyFrame extends Frame {
    
    static int id = 0;// There may be multiple windows , A counter is required to distinguish title

    public MyFrame(int x, int y, int w, int h, Color color) {
    
        super("MyFrame" + (++id));// Call the parent constructor 

        // You need to set visibility 
        setVisible(true);// Inherit , Just call the parent method directly 

        // Set window size 
        setSize(w, h);
        // The initial position of the pop-up 
        setLocation(x, y);// Screen coordinates （0,0） spot , In the upper left corner 

        //setBounds(x,y,w,h);// Equivalent to the above two , Set the position and size directly 

        // Set the background color  Color
        setBackground(color);

        // Set the size fixed 
        setResizable(false);// Can't change 


    }

}

Running results ：

2.Panel panel

Frame A panel is added in the , After that, all components are added in the panel

meanwhile , Solved the problem of closing the window

package com.song.lesson01;

import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;

// The panel can be seen as a space , But it can't exist alone 
public class TestPanel {
    
    public static void main(String[] args) {
    
        Frame frame = new Frame();
        // The concept of layout 
        Panel panel = new Panel();

        // Setting up layout 
        frame.setLayout(null);

        // coordinate 、 background 
        frame.setBounds(300, 300, 500, 500);
        frame.setBackground(new Color(40, 161, 35));

        //panel Set coordinates , be relative to frame—— Relative coordinates 
        panel.setBounds(50, 50, 400, 400);
        panel.setBackground(new Color(157, 115, 24));

        // Add panels to frame in 
        frame.add(panel);

        // Set visibility 
        frame.setVisible(true);

        // Monitoring events : Listen for window closing events 
        /* direct new One WindowListener, Many methods need to be rewritten ; Therefore, consider the adapter mode , Write only the methods you need */
        // Adapter pattern , Just choose the method you want 
        frame.addWindowListener(new WindowAdapter() {
    
            // Click on what to do when the window closes 
            @Override
            public void windowClosing(WindowEvent e) {
    
                // End procedure 
                System.exit(0);
            }
        });

    }
}

Running results ：

2.3 Layout manager

• Fluid layout

package com.song.lesson01;

import java.awt.*;

public class TestFlowLayout {
    
    public static void main(String[] args) {
    
        Frame frame = new Frame();

        // Components -- Button 
        Button button1 = new Button("button1");
        Button button2 = new Button("button2");
        Button button3 = new Button("button3");

        // Set to flow layout 
        //frame.setLayout(new FlowLayout());
        frame.setLayout(new FlowLayout(FlowLayout.LEFT));

        frame.setSize(200, 200);

        // Add the button 
        frame.add(button1);
        frame.add(button2);
        frame.add(button3);

        frame.setVisible(true);
    }
}

• Southeast northwest middle

package com.song.lesson01;

import java.awt.*;

public class TestBorderLayout {
    
    public static void main(String[] args) {
    
        Frame frame = new Frame();

        Button button1 = new Button("East");
        Button button2 = new Button("West");
        Button button3 = new Button("South");
        Button button4 = new Button("North");
        Button button5 = new Button("Center");

        frame.add(button1, BorderLayout.EAST);
        frame.add(button2, BorderLayout.WEST);
        frame.add(button3, BorderLayout.SOUTH);
        frame.add(button4, BorderLayout.NORTH);
        frame.add(button5, BorderLayout.CENTER);

        frame.setSize(200, 200);
        frame.setVisible(true);


    }
}

• Table layout

package com.song.lesson01;

import java.awt.*;

public class TestGridLayout {
    
    public static void main(String[] args) {
    
        Frame frame = new Frame();

        Button button1 = new Button("1");
        Button button2 = new Button("2");
        Button button3 = new Button("3");
        Button button4 = new Button("4");
        Button button5 = new Button("5");
        Button button6 = new Button("6");

        frame.setLayout(new GridLayout(3, 2));//3 That's ok 2 Column 
        frame.add(button1);
        frame.add(button2);
        frame.add(button3);
        frame.add(button4);
        frame.add(button5);
        frame.add(button6);

        frame.pack();//Java function , Auto fill 
        frame.setVisible(true);

    }
}

practice

1.frame

2.4 Panels

border

​ Left ：button

in ： panel

Right ：button

package com.song.lesson01;

import java.awt.*;

public class Test {
    
    public static void main(String[] args) {
    
        // General layout Frame
        Frame frame = new Frame();
        frame.setLayout(new GridLayout(2, 1));//2 That's ok 1 Column , Separate the upper and lower structures 

        frame.setSize(400, 300);
        frame.setVisible(true);
        frame.setBackground(Color.pink);

        //4 Panels 
        Panel panel1 = new Panel(new BorderLayout());// Divide the above into East, West, north, South and middle , Isolate 2 The side button
        Panel panel2 = new Panel(new GridLayout(2, 1));// In the middle is 2 That's ok 1 Column 
        Panel panel3 = new Panel(new BorderLayout());
        Panel panel4 = new Panel(new GridLayout(2, 2));

        // above 
        panel1.add(new Button("East-1"), BorderLayout.EAST);
        panel1.add(new Button("West-1"), BorderLayout.WEST);

        panel2.add(new Button("p2-btn-1"));
        panel2.add(new Button("p2-btn-2"));
        panel1.add(panel2, BorderLayout.CENTER);

        // below 
        panel3.add(new Button("East-2"), BorderLayout.EAST);
        panel3.add(new Button("West-2"), BorderLayout.WEST);
        for (int i = 1; i <= 4; i++) {
    
            panel4.add(new Button("p4-btn-" + i));
        }
        panel3.add(panel4, BorderLayout.CENTER);

        frame.add(panel1);
        frame.add(panel3);


    }
}

summary

1.Frame It's a top-level window

2.Panel You can't show it alone , Must be placed in a container （Frame） in

3. Layout manager

• Fluid layout
• Southeast northwest middle
• Table layout

4. size 、 location 、 The background color 、 visibility 、 monitor

2.4 Event monitoring

package com.song.lesson02;

import com.sun.javafx.logging.JFRInputEvent;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class TestActionEvent {
    
    public static void main(String[] args) {
    
        // Press the button , Trigger an event 
        Frame frame = new Frame();
        Button button = new Button("button");

        // Because of the need addActionListener() Need one ActionListener, So construct a 
        MyActionListener myActionListener = new MyActionListener();
        button.addActionListener(myActionListener);

        frame.add(button, BorderLayout.CENTER);
        frame.pack();

        windowClose(frame);
        frame.setVisible(true);
    }

    // Event that closes the window 
    private static void windowClose(Frame frame) {
    
        frame.addWindowListener(new WindowAdapter() {
    
            @Override
            public void windowClosing(WindowEvent e) {
    
                System.exit(0);
            }
        });
    }

}

class MyActionListener implements ActionListener {
    
    @Override
    public void actionPerformed(ActionEvent e) {
    
        System.out.println("lalalala");
    }
}

Multiple buttons , Share an event

package com.song.lesson02;

import org.omg.PortableInterceptor.ACTIVE;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class TestActionTwo {
    
    public static void main(String[] args) {
    
        // Two buttons   Implement the same monitor 
        // Start   stop it 
        Frame frame = new Frame();
        Button button1 = new Button("start");
        Button button2 = new Button("stop");

        button1.setActionCommand("button1-start");
        //button2.setActionCommand("button2-stop");// Show default values when definitions are not displayed stop

        MyAction myAction = new MyAction();
        button1.addActionListener(myAction);
        button2.addActionListener(myAction);

        frame.add(button1, BorderLayout.NORTH);
        frame.add(button2, BorderLayout.SOUTH);
        frame.setSize(400, 400);
        frame.setVisible(true);


    }
}

class MyAction implements ActionListener {
    
    @Override
    public void actionPerformed(ActionEvent e) {
    
        //getActionCommand() Get information about the button 
        System.out.println(" The button is clicked ：msg " + e.getActionCommand());

    }
}

2.5 Input box

package com.song.lesson02;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class TestText01 {
    
    public static void main(String[] args) {
    
        // normal main There is only one startup in the method 
        MyFrame myFrame = new MyFrame();

    }
}

class MyFrame extends Frame {
    
    public MyFrame() {
    
        TextField textField = new TextField();
        add(textField);

        // Listen to the text input in this text box 
        MyActionListener2 myActionListener2 = new MyActionListener2();
        // Press down Enter, Will trigger an event in the input box 
        textField.addActionListener(myActionListener2);

        // Set the code to replace the display 
        textField.setEchoChar('*');

        setVisible(true);
        setSize(400, 400);
        pack();

    }
}

class MyActionListener2 implements ActionListener {
    
    @Override
    public void actionPerformed(ActionEvent e) {
    
        TextField field = (TextField) e.getSource();// Get some resources , Return to an object 
        System.out.println(field.getText());
        ;// Get the text in the input box 
        field.setText("");// Press enter to clear 
    }
}

2.6 Clean Calculator Beta , Combine + Inner class

oop principle ： Combine , Greater than inheritance ( Give priority to combinations )

Inherit ：

class A extends B{
        }

Combine ：

class A{
        public B b;}

Implementation method ：（ Process oriented )

package com.song.lesson02;import java.awt.*;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;// Clean Calculator Beta public class TestCalculator { public static void main(String[] args) { Calculator myFrame2 = new Calculator(); }}// Calculator class class Calculator extends Frame { public Calculator() { //3 Textboxes 、1 Button 、1 A label  TextField textField1 = new TextField(10);// Number of characters , That is, the size of the box  TextField textField2 = new TextField(10); TextField textField3 = new TextField(20); Label label = new Label("+"); Button btn = new Button("="); btn.addActionListener(new MyCalculatorListener(textField1, textField2, textField3)); // Layout  setLayout(new FlowLayout()); add(textField1); add(label); add(textField2); add(btn); add(textField3); setVisible(true); pack(); }}// Monitor class class MyCalculatorListener implements ActionListener { // Get three variables  private TextField num1, num2, num3; public MyCalculatorListener(TextField num1, TextField num2, TextField num3) { this.num1 = num1; this.num2 = num2; this.num3 = num3; } @Override public void actionPerformed(ActionEvent e) { //1. Get the addend and the addend  int n1 = Integer.parseInt(num1.getText()); int n2 = Integer.parseInt(num2.getText()); //2. Addition operation 、 Put it in the third box  num3.setText("" + (n1 + n2)); // Clear the first two boxes  num1.setText(""); num2.setText(""); }}

Method improvement 1：( Combine )

package com.song.lesson02;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

// Clean Calculator Beta 
public class TestCalculator {
    
    public static void main(String[] args) {
    
        new Calculator().loadFrame();
    }
}

// Calculator class 
class Calculator extends Frame {
    
    // attribute 
    TextField num1, num2, num3;


    // Method 
    public void loadFrame() {
    
        //3 Textboxes 、1 Button 、1 A label 
        num1 = new TextField(10);// Number of characters , That is, the size of the box 
        num2 = new TextField(10);
        num3 = new TextField(20);
        Label label = new Label("+");
        Button btn = new Button("=");

        btn.addActionListener(new MyCalculatorListener(this));//this Is refers to Calculator own 

        // Layout 
        setLayout(new FlowLayout());
        add(num1);
        add(label);
        add(num2);
        add(btn);
        add(num3);

        setVisible(true);
        pack();


    }
}

// Monitor class 
class MyCalculatorListener implements ActionListener {
    
    // Get calculator object , Combine one class with another 
    Calculator cal = null;


    public MyCalculatorListener(Calculator calculator) {
    
        this.cal = calculator;
    }

    @Override
    public void actionPerformed(ActionEvent e) {
    
        //1. Get the addend and the addend 
        //2. Addition operation 、 Put it in the third box 
        // Clear the first two boxes 
        int n1 = Integer.parseInt(cal.num1.getText());
        int n2 = Integer.parseInt(cal.num2.getText());
        cal.num3.setText("" + (n1 + n2));
        cal.num1.setText("");
        cal.num2.setText("");

    }
}

Method improvement 2：( Completely object-oriented —— Inner class )

package com.song.lesson02;import java.awt.*;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;// Clean Calculator Beta public class TestCalculator { public static void main(String[] args) { new Calculator().loadFrame(); }}// Calculator class class Calculator extends Frame { // attribute  TextField num1, num2, num3; // Method  public void loadFrame() { //3 Textboxes 、1 Button 、1 A label  num1 = new TextField(10);// Number of characters , That is, the size of the box  num2 = new TextField(10); num3 = new TextField(20); Label label = new Label("+"); Button btn = new Button("="); btn.addActionListener(new MyCalculatorListener());//this Is refers to Calculator own  // Layout  setLayout(new FlowLayout()); add(num1); add(label); add(num2); add(btn); add(num3); setVisible(true); pack(); } // Monitor class , Set to inner class  // The biggest benefit of inner classes , You can have unimpeded access to methods of external classes  private class MyCalculatorListener implements ActionListener { @Override public void actionPerformed(ActionEvent e) { //1. Get the addend and the addend  //2. Addition operation 、 Put it in the third box  // Clear the first two boxes  int n1 = Integer.parseInt(num1.getText()); int n2 = Integer.parseInt(num2.getText()); num3.setText("" + (n1 + n2)); num1.setText(""); num2.setText(""); } }}

2.7 paint brush

package com.song.lesson03;

import java.awt.*;

public class TestPaint {
    
    public static void main(String[] args) {
    
        new MyPaint().loadFrame();
    }
}

class MyPaint extends Frame {
    

    public void loadFrame() {
    
        setBounds(200, 200, 800, 500);
        setVisible(true);
    }

    // paint brush 
    @Override
    public void paint(Graphics g) {
    
        //super.paint(g);
        // The brush needs color 
        g.setColor(Color.pink);
        // The brush needs to be able to draw 
        g.fillOval(100, 100, 100, 100);// Solid circle 

        g.setColor(Color.green);
        g.fillRect(150, 200, 200, 200);

        // When the brush is used up, you need to restore it to its original color 
        g.setColor(Color.black);
    }
}

2.8 Mouse monitor

Purpose ： Realize the mouse drawing （ Click on ）

Ideas ：

package com.song.lesson03;

import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.ArrayList;
import java.util.Iterator;

public class TestMouseListener {
    
    public static void main(String[] args) {
    
        new MyFrame(" drawing ");

    }
}

// My own class 
class MyFrame extends Frame {
    
    // Painting needs a brush , Need to monitor the current mouse position , You need a collection to store this 
    //ArrayList  Class is an array that can be dynamically modified , The difference from ordinary arrays is that there is no fixed size limit , We can add or remove elements .
    ArrayList points;

    public MyFrame(String title) {
    
        super(title);
        setBounds(200, 200, 400, 300);
        // Store mouse clicks 
        points = new ArrayList<>();

        setVisible(true);

        // Mouse monitor , Facing this window 
        this.addMouseListener(new MyMouseListener());

    }

    @Override
    public void paint(Graphics g) {
    
        // Drawing a picture , Monitor mouse events 
        // Using Iterators , Draw all the dots in the set 
        Iterator iterator = points.iterator();
        while (iterator.hasNext()) {
    
            Point point = (Point) iterator.next();
            g.setColor(Color.blue);
            g.fillOval(point.x, point.y, 10, 10);
        }


    }

    // Add a point to the interface , Draw up 
    public void addPaint(Point point) {
    
        // Add points to the set of storage points 
        points.add(point);
    }


    // Monitor class 
    // Adapter pattern 
    private class MyMouseListener extends MouseAdapter {
    
        // mouse ： Press down 、 Spring up 、 Release 

        @Override
        public void mousePressed(MouseEvent e) {
    
            MyFrame frame = (MyFrame) e.getSource();
            // When we click on this , It creates a point in the interface 
            // This point is the point of the mouse , Add to collection 
            frame.addPaint(new Point(e.getX(), e.getY()));

            // Every time you click the mouse, you have to redraw the window , Otherwise, the canvas will not display 
            frame.repaint();// Refresh 

        }
    }
}

2.9 Window listening

// Inner class methods 
package com.song.lesson03;


import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class TestWindow {
    
    public static void main(String[] args) {
    
        new WindowFrame();
    }
}

class WindowFrame extends Frame {
    
    public WindowFrame() {
    
        setVisible(true);
        setBounds(100, 100, 300, 300);
        setBackground(Color.pink);
        addWindowListener(new MyWindowListener());


    }

    // Inner class , convenient 
    class MyWindowListener extends WindowAdapter {
    
        @Override
        public void windowClosing(WindowEvent e) {
    
            //setVisible(false);// Just hide , Not normally closed ; Through button , Hide the current window 
            System.exit(0);// The normal exit 
        }
    }

}

// Anonymous inner class package com.song.lesson03;import java.awt.*;import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;public class TestWindow { public static void main(String[] args) { new WindowFrame(); }}class WindowFrame extends Frame { public WindowFrame() { setVisible(true); setBounds(100, 100, 300, 300); setBackground(Color.pink); // Anonymous inner class , More recommended  this.addWindowListener( new WindowAdapter() { // close window  @Override public void windowClosing(WindowEvent e) { System.out.println("Window closing"); System.exit(0); } // Activate window  @Override public void windowActivated(WindowEvent e) { Frame frame = (Frame) e.getSource(); frame.setTitle(" Is activated "); System.out.println("Window activated"); } } ); }}

2.10 Keyboard monitor

package com.song.lesson03;

import java.awt.*;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

public class TestKeyListener {
    
    public static void main(String[] args) {
    
    new KeyFrame();
    }
}

class KeyFrame extends Frame{
    
    KeyFrame(){
    
        setBounds(100,100,400,400);
        setVisible(true);

        this.addKeyListener(new KeyAdapter() {
    
            @Override
            public void keyPressed(KeyEvent e) {
    
                // Which key is pressed on the keyboard , The code of the current keyboard l
                int keyCode=e.getKeyCode();// There is no need to record the value , Use static attributes directly VK_XXX
                System.out.println(keyCode);
                if(keyCode==KeyEvent.VK_UP){
    
                    System.out.println(" You press the up button ");
                }
                // According to the different operations pressed , Can produce different results 
            }
        });
    }


}

3.Swing

Use Swing To get a container Container, And put things on it ;AWT Unwanted , direct add

 Container container=this.getContentPane();

Consider using constructors or initialization functions to define .

3.1 window JFrame

package com.song.lesson04;

import sun.java2d.loops.Blit;

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

public class JFrameDemo {
    

    public static void main(String[] args) {
    
        // Create a window 
        new MyFrame().init();
    }
}
class MyFrame extends JFrame{
    
    //init(); initialization 
    public void init(){
    
        this.setVisible(true);
        this.setBounds(100,100,300,300);



        //label It's actually on the container , Let the container initialize explicitly 

        // Get a container 
        Container container=this.getContentPane();
        container.setBackground(Color.blue);

        // Set text 
        JLabel jLabel = new JLabel(" welcome ！");
        container.add(jLabel);
        jLabel.setBackground(Color.PINK);

        // Closing event 
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    }
}

3.2 Popup JDialog

JDialog, There is a shutdown event by default , There is no need to write

package com.song.lesson04;

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

// main window 
public class DialogDemo extends JFrame {
    
    DialogDemo() {
    
        this.setVisible(true);
        this.setBounds(100, 100, 700, 500);
        //this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);// Set default off 

        //JFrame  Put things , Containers 
        Container container = this.getContentPane();
        // Absolute layout 
        container.setLayout(null);
        // Button 
        JButton jButton = new JButton(" Click to pop up a dialog box ");// establish 
        jButton.setBounds(30, 30, 200, 59);

        // A pop-up window pops up when you click the button 
        jButton.addActionListener(new ActionListener() {
    
            @Override
            public void actionPerformed(ActionEvent e) {
    
                // Popup 
                new MyDialog();
            }
        });
        container.add(jButton);


    }

    public static void main(String[] args) {
    
        new DialogDemo();
    }
}

// Pop up window 
class MyDialog extends JDialog {
    
    public MyDialog() {
    
        this.setVisible(true);
        this.setBounds(300, 300, 500, 500);
        
        Container container = new Container();
        container.setLayout(null);
        container.add(new JLabel(" learn Java"));

        //this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }
}

3.3 label JLable

new JLable(" label ");

1. Put an icon on the label （Icon Interface ）

package com.song.lesson04;


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

public class IconDemo extends JFrame implements Icon {
    

    private int width;
    private int height;

    // No arguments structure 
    public IconDemo() {
    

    }

    // There are parametric structures 
    public IconDemo(int width, int height) {
    
        this.height = height;
        this.width = width;
    }

    public void init() {
    
        IconDemo iconDemo = new IconDemo(15, 15);

        // Icons can be placed on labels , It can also be placed on the button 
        JLabel label = new JLabel("icontest", iconDemo, SwingConstants.CENTER);

        Container container = getContentPane();// Be careful ！！
        container.add(label);//lable To be added to the container 

        this.setVisible(true);
        this.setBounds(100, 100, 400, 400);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    }


    public static void main(String[] args) {
    
        new IconDemo().init();
    }

    @Override
    public void paintIcon(Component c, Graphics g, int x, int y) {
    
        g.fillOval(x, y, width, height);
    }

    @Override
    public int getIconWidth() {
    
        return this.width;
    }

    @Override
    public int getIconHeight() {
    
        return this.height;
    }
}

2. Put a picture on the label （ImageIcon class ）

package com.song.lesson04;

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

public class ImageIconDemo extends JFrame {
    

    public ImageIconDemo() {
    
        // Get image address 

        JLabel label = new JLabel("ImageIcon");

        // Get current IamgeIconDemo Peer resources of this class , Return an address URL. Try not to write dead ！！！
        URL url = ImageIconDemo.class.getResource("test.jpg");
        ImageIcon imageIcon = new ImageIcon(url);// Note that ImageIcon class , Do not name conflicts 
        label.setIcon(imageIcon);// Set picture labels 
        label.setHorizontalAlignment(SwingConstants.CENTER);// picture centering 

        Container container = getContentPane();
        container.add(label);

        setVisible(true);
        setBounds(100, 100, 500, 500);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    }

    public static void main(String[] args) {
    
        new ImageIconDemo();
    }

}

3.4 panel JPanle

package com.song.lesson04;

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

public class JPanelDemo extends JFrame {
    
    public JPanelDemo(){
    
        Container container=getContentPane();
        container.setLayout(new GridLayout(2,1,10,10));// Later parameters 10 It's spacing m
        JPanel panle=new JPanel(new GridLayout(1,3));
        panle.add(new Button("button 1"));
        panle.add(new Button("button 2"));
        panle.add(new Button("button 3"));

        JPanel panle2=new JPanel(new GridLayout(2,2));
        panle2.add(new Button("button 1"));
        panle2.add(new Button("button 2"));
        panle2.add(new Button("button 3"));
        panle2.add(new Button("button 4"));

        JPanel panle3=new JPanel(new GridLayout(2,1));
        panle3.add(new Button("button 1"));
        panle3.add(new Button("button 2"));

        container.add(panle);
        container.add(panle2);
        container.add(panle3);

        setVisible(true);
        setSize(300,300);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
    
        new JPanelDemo();
    }

}

Scroll bar

package com.song.lesson04;

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

public class JScollDemo extends JFrame {
    

    // The scroll bar normally does not , Only when the size is exceeded 
    public JScollDemo() {
    
        Container container = getContentPane();

        // Text domain 
        JTextArea jTextArea = new JTextArea(20, 50);
        jTextArea.setText("Welcome!!!!!!!!!!!!!!!");

        //Scroll panel 
        JScrollPane jScrollPane = new JScrollPane(jTextArea);

        container.add(jScrollPane);

        this.setVisible(true);
        this.setBounds(100, 100, 400, 400);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);


    }

    public static void main(String[] args) {
    
        new JScollDemo();
    }
}

3.5 Button JButton

Picture button

package com.song.lesson04;

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

public class JButtonDemo01 extends JFrame {
    

    public JButtonDemo01() {
    
        Container container = getContentPane();

        // Turn a picture into an icon 
        URL resource = JButtonDemo01.class.getResource("test.jpg");
        Icon icon = new ImageIcon(resource);// Turn the picture into an icon 

        // Put the icon on the button 
        JButton jButton = new JButton("button");
        jButton.setIcon(icon);
        jButton.setToolTipText(" Picture button ");

        //add
        container.add(jButton);

        setVisible(true);
        setBounds(100,100,300,300);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    }

    public static void main(String[] args) {
    
        new JButtonDemo01();
    }
}

• Radio buttons

package com.song.lesson04;

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

public class JButtonDemo02 extends JFrame{
    
    public JButtonDemo02(){
    
        Container container = this.getContentPane();

        // Radio buttons 
        JRadioButton jRadioButton1 = new JRadioButton("button01");
        JRadioButton jRadioButton2 = new JRadioButton("button02");
        JRadioButton jRadioButton3 = new JRadioButton("button03");

        // Because only one radio box can be selected , Generally, they are grouped , Only one member of a group can be selected 
        ButtonGroup group = new ButtonGroup();
        group.add(jRadioButton1);
        group.add(jRadioButton2);
        group.add(jRadioButton3);

        //add
        container.add(jRadioButton1,BorderLayout.CENTER);
        container.add(jRadioButton2,BorderLayout.NORTH);
        container.add(jRadioButton3,BorderLayout.SOUTH);

        this.setVisible(true);
        this.setBounds(100, 100, 300, 300);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
    
        new JButtonDemo02();
    }
}

• Check box

package com.song.lesson04;

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

public class JButtonDemo03 extends JFrame {
    
    public JButtonDemo03() {
    
        Container container = this.getContentPane();

        // Checkbox 
        JCheckBox box01 = new JCheckBox("JCheckBox01");
        JCheckBox box02 = new JCheckBox("JCheckBox02");
        JCheckBox box03 = new JCheckBox("JCheckBox03");


        //add
        container.add(box01, BorderLayout.CENTER);
        container.add(box02, BorderLayout.NORTH);
        container.add(box03, BorderLayout.SOUTH);

        this.setVisible(true);
        this.setBounds(100, 100, 300, 300);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
    
        new JButtonDemo03();
    }
}

3.6 list

• A drop-down box

package com.song.lesson05;

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

public class ComboboxDemo01 extends JFrame {
    

    public ComboboxDemo01() {
    
        Container container = this.getContentPane();


        JComboBox status = new JComboBox();
        status.addItem(null);
        status.addItem(" Is hit ");
        status.addItem(" It's off the shelf ");
        status.addItem(" To be shown soon ");

        //status.addActionListener(); Get the selected content 

        container.add(status);

        this.setVisible(true);
        this.setBounds(100, 100, 300, 300);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }


    public static void main(String[] args) {
    
        new ComboboxDemo01();
    }
}

• List box

package com.song.lesson05;

import javax.swing.*;
import java.awt.*;
import java.util.List;
import java.util.Vector;

public class ComboboxDemo02 extends JFrame {
    
    public ComboboxDemo02() {
    

        Container container = this.getContentPane();

        // Generate the contents of the list , You can use arrays , Static , Cannot add dynamically 
        String[] contents = {
    "1", "2", "3"};
        // What needs to be put in the list 
        JList jList = new JList(contents);

        // Generate the contents of the list , You can use data structures , Dynamic addition 
        Vector contents2 = new Vector();
        // What needs to be put in the list 
        JList jList2 = new JList(contents2);
        contents2.add("1111");
        contents2.add("222");
        contents2.add("33");
        contents2.add("4");


        //container.add(jList);
        container.add(jList2);

        this.setVisible(true);
        this.setBounds(100, 100, 300, 300);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }


    public static void main(String[] args) {
    
        new ComboboxDemo02();
    }
}

Application scenarios ：

• A drop-down box —— Select a region or some individual options
• List box —— Used to show some information , General dynamic expansion

3.7 The text box

• The text box

package com.song.lesson05;

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

public class TestTextDemo01 extends JFrame {
    
    public TestTextDemo01() {
    

        Container container = this.getContentPane();

        JTextField jTextField = new JTextField("Hello");
        JTextField jTextField2 = new JTextField("world", 20);

        container.add(jTextField, BorderLayout.SOUTH);
        container.add(jTextField2, BorderLayout.NORTH);

        this.setVisible(true);
        this.setBounds(100, 100, 300, 300);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }


    public static void main(String[] args) {
    
        new TestTextDemo01();
    }
}

• Password box

package com.song.lesson05;

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

public class TestTextDemo02 extends JFrame {
    
    public TestTextDemo02() {
    

        Container container = this.getContentPane();

        // For the convenience of layout , Try to be in the panel 

        JPasswordField jPasswordField = new JPasswordField();//***
        jPasswordField.setEchoChar('*');

        container.add(jPasswordField);


        this.setVisible(true);
        this.setBounds(100, 100, 300, 300);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }


    public static void main(String[] args) {
    
        new TestTextDemo02();
    }
}

• Text domain

The biggest difference between a text field and a text box is that the text field allows users to enter multiple lines of text information .

The text field is mainly used with the panel , Refer to the scroll bar settings .

4. actual combat —— Greedy Snake games

• frame ： If the time slice is small enough , It's animation. , One second 30 frame 60 frame , Together, it's animation ; When disassembled, it is a static picture
• Keyboard monitor
• Timer Timer