Question

import java.awt.FlowLayout;  
import java.awt.event.*;  
import javax.swing.*;  
public class Cylinder extends JFrame implements ActionListener{  

    JLabel lblRadius = new JLabel("Enter the Radius");  
    JLabel lblHeight = new JLabel("Enter the Height");  
    JTextField txtRadius  = new JTextField(10);  
    JTextField txtHeight = new JTextField(10);  
    JButton btnCalculate = new JButton("Calculate");  
    JButton btnClear = new JButton("Clear");  
    JTextField txtOutput = new JTextField(20);  
    JPanel p = new JPanel();  
    FlowLayout layout;  
    public Cylinder(){  
        super("Calculator");  
        setSize(300,300);  
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
        layout = new FlowLayout();  
        p.setLayout(layout);  
        p.add(lblRadius);  
        p.add(txtRadius);  
        p.add(lblHeight);  
        p.add(txtHeight);  
        p.add(btnCalculate);  
        p.add(btnClear);  
        p.add(txtOutput);  
        p.add(p);  

        setVisible(true);  

        btnCalculate.addActionListener(this);  
        btnClear.addActionListener(this);  
    }  

    @Override  
    public void actionPerformed(ActionEvent e) {  
        Object source = e.getSource();  
        int radius = Integer.parseInt(txtRadius.getText());  
        int height = Integer.parseInt(txtHeight.getText());  
        if (source.equals(btnCalculate)){  
            double volume = (Math.PI * radius * radius)*height;  
            txtOutput.setText("The Volume is: "+ Math.round(volume));  
        }  

        if (source.equals(btnClear)){  
            txtRadius.setText("");  
            txtHeight.setText("");  
            txtOutput.setText("");  
        }  
    }  
    public static void main(String[] args) {  
         new Cylinder();  
    }  
}

我正在尝试向我的netbeans项目添加GUI但是收到错误消息：

线程中的异常＆＃34; main＆＃34; java.lang.IllegalArgumentException：添加容器的父母自己 java.awt.Container.checkAddToSelf（Container.java:472）at java.awt.Container.addImpl（Container.java:1083）at java.awt.Container.add（Container.java:410）at cylinder.Cylinder。（Cylinder.java:38）at cylinder.Cylinder.main（Cylinder.java:68）Java结果：1

Answer 1

因为这行代码

p.add(p);

解决方案：将此行更改为add(p);，因为您无法将面板放入自身。我相信你的目标是将面板放在你继承的JFrame上。

线程＆＃34; main＆＃34;中的例外情况java.lang.IllegalArgumentException：将容器的父级添加到自身

1 个答案: