How to use GUI functions to implement graphical user interface and user interaction in Java

How to use GUI functions to implement graphical user interface and user interaction in Java

Introduction:
In Java programming, graphical user interface (Graphical User Interface, GUI) is a common form of user interface that realizes interaction between users and programs through the use of graphical elements (such as buttons, text boxes, labels, etc.) and interactive operations (such as mouse clicks, keyboard input, etc.). Java provides a rich GUI function library that can simplify the process of creating GUI programs. This article will introduce the basic steps of how to use GUI functions to implement graphical user interface and user interaction, and give specific code examples.

1. Preparation
To create a GUI program in Java, you must first add the required packages. In this example, we need to import the following packages:
import javax.swing.JFrame; / /JFrame class provides a basic window and is the main container of GUI programs
import javax.swing.JLabel; //JLabel class is used to display text or images
import javax.swing.JButton; //JButton class Used to create buttons
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent; //ActionEvent class is used to handle button click events

2. Create window
The window is the main container of the GUI program and can accommodate other GUI components (such as buttons, text boxes, etc.). In Java, we can create a window by inheriting the JFrame class. The specific code is as follows:

public class MyWindow extends JFrame {

public MyWindow() {
    setTitle("Java GUI程序");     //设置窗口标题
    setSize(400, 300);           //设置窗口大小
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  //设置窗口关闭操作
    setLocationRelativeTo(null);  //将窗口位置设置为屏幕中央
    setLayout(null);             //禁用默认布局管理器
}

}

3. Add GUI components
After creating the window, we can add GUI components to the window, such as labels, buttons, etc. In Java, we can create labels using JLabel class and buttons using JButton class. The following is a code example for adding labels and buttons to the window:

public class MyWindow extends JFrame {

public MyWindow() {
    //窗口初始化设置省略...
    
    JLabel label = new JLabel("Hello, Java GUI!");   //创建一个标签
    label.setBounds(50, 50, 200, 30);                 //设置标签的位置和大小
    add(label);                                      //将标签添加到窗口中
    
    JButton button = new JButton("点击我");            //创建一个按钮
    button.setBounds(50, 100, 100, 30);               //设置按钮的位置和大小
    add(button);                                     //将按钮添加到窗口中
}

}

4. Handling user interaction
In graphical users In the interface, users operate the program by interacting with GUI components. We can add a click event handler to the button to respond to the click of the button. The following is a simple code example for button click event handling:

public class MyWindow extends JFrame {

public MyWindow() {
    //窗口初始化设置省略...
    
    //创建标签和按钮的代码省略...
    
    button.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            label.setText("按钮被点击了！");         //修改标签的文本
        }
    });
}

}

Summary:
This article introduces how to The basic steps of using GUI functions to implement graphical user interface and user interaction. We can create windows by inheriting the JFrame class and create labels and buttons using the JLabel class and JButton class. By adding a click event handler to the button, we can respond to button clicks. I hope this article can help you get started with Java GUI programming and create your own GUI program smoothly.

References:

1. Java official documentation-https://docs.oracle.com/javase/tutorial/uiswing/
2. Java Swing tutorial-https: //www.javatpoint.com/java-swing

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