Question

我正在从教程中学习基本的Java GUI编程，并且此代码应该生成一个带有标题，一些文本和一些工具提示文本的窗口。它不会产生任何东西。谁能告诉我为什么它不起作用？

//In a class called apples:

import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;

public class apples extends JFrame {

    private JLabel item1;

    public apples() {
        super("Title");
        setLayout(new FlowLayout());

        item1 = new JLabel("This is some displayed text");
        item1.setToolTipText("This is some tooltip text.");
        add(item1);
    }

}

//In the main class class1:
import javax.swing.JFrame;

class class1 {
    public static void main(String args[]) {

        apples green = new apples();
        green.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

}

Answer 1

您可以尝试以下方法吗？

class Class1 {
    public static void main(String args[]) {
        apples green = new apples();
        green.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        green.setSize(1000, 500); // set window's size.
        green.pack(); // packs the components closely together.
        green.setVisible(true); // makes the window visible.
    }
}

JFrame窗口未显示

1 个答案: