JFrame代码可以编译并运行，但不会打开窗口 [英] JFrame code compiles and runs, but does not open window

问题描述

在这里您将看到我的代码: 我只是试图制作一个小窗口，显示你好，Java！".

Here you will see my code: I am just trying to make a little window that displays "Hello, Java!".

我当前正在Ubuntu 14.04上运行.为了更深入地研究我的问题，当我运行该程序时，带有咖啡杯的图标会显示出来，就像有一个窗口，但是没有附加窗口，如果单击该窗口，则不会弹出任何窗口.

I am currently running on Ubuntu 14.04. To go more in depth with my problem, the icon with the coffee cup shows up when I run the program like there is a window, but there is not window attached to it and if clicked, no window pops up.

任何帮助将不胜感激！

public class HelloJava1 extends javax.swing.JComponent
{
    public static void main(String[] args)
    {
        javax.swing.JFrame f = new javax.swing.JFrame("HelloJava1");
        f.setSize(300, 300);
        f.getContentPane().add(new HelloJava1());
        f.setVisible(true);
    }   

    public void paintComponent(java.awt.Graphics g)
    {
        g.drawString("Hello, Java!", 125, 95);
    }
}

此外，我正在使用javac HelloJava1.java通过命令行进行编译，并使用java HelloJava1进行了运行.

Additionally, I am compiling via command line using javac HelloJava1.java and running using java HelloJava1.

我正在通过gedit编写代码.

I am writing the code via gedit.

推荐答案

此代码应可靠运行:

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

public class HelloJava1 extends JComponent {

    public static void main(String[] args) {
        Runnable r = new Runnable() {
            public void run() {
                JFrame f = new JFrame("HelloJava1");
                // f.setSize(300, 300);  better to pack() the frame
                f.getContentPane().add(new HelloJava1());
                // pack should be AFTER components are added..
                f.pack();
                f.setVisible(true);
            }
        };
        // Swing GUIs should be created and updated on the EDT
        SwingUtilities.invokeLater(r);
    }    

    @Override  // good practice..
    public void paintComponent(java.awt.Graphics g) {
        // always call super method 1st!
        super.paintComponent(g);
        g.drawString("Hello, Java!", 125, 95);
    }

    // instead of setting the size of components, it is 
    // better to override the preferred size.
    @Override
    public Dimension getPreferredSize() {
        return new Dimension(300,300);
    }
}

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