Question

大家好，我目前正在尝试为学校完成作业，但我已经陷入困境，这里没有任何与我的问题直接相关的内容。该任务是创建一个GUI应用程序，显示客户访问Joe的总数。有些人可能从学校知道这个问题。 https://bb1ap.tamut.edu/bbcswebdav/pid-281014-dt-content-rid-800291_1/courses/80706_15/week08_activity_25-27.pdf在附件pdf的底部是我遇到的问题以及成品应该是什么样子的图像。我似乎无法创建两个单独的标题边框。非常感谢任何帮助。如果你可以解释它，就像我的五年级学生更好！

//Programmer: Davis Bentley
//Date: 10/21/2015
//Purpose: To allow user to calculate auto service cost

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

public class autoCalc extends JFrame {

private JPanel topPanel;
private JPanel centerPanel;
private JLabel messageLabel1, messageLabel2;
private JTextField autoTextField1, autoTextField2;
private JButton calcButton, exitButton;
private final int WINDOW_WIDTH = 450;
private final int WINDOW_HEIGHT = 600;
JCheckBox oil = new JCheckBox("Oil Change ($26.00)");
JCheckBox lube = new JCheckBox("Lube Job ($18.00)");
JCheckBox radiator = new JCheckBox("Radiator FLush($30.00");
JCheckBox trans = new JCheckBox("Transmission FLush ($80.00)");
JCheckBox inspect = new JCheckBox("Inspection ($15.00)");
JCheckBox muffler = new JCheckBox("Muffler Replacement ($100.00)");
JCheckBox tire = new JCheckBox("Tire Rotation ($20.00)");

public autoCalc(){
    super("Joe's Automotive");
    setSize(WINDOW_WIDTH, WINDOW_HEIGHT);

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    buildPanel();
    setVisible(true);
}
private void buildPanel(){

    JFrame frame = new JFrame("Joe's Automotive");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(topPanel);
    frame.add(centerPanel);

    topPanel = new JPanel();
    topPanel.setBorder(BorderFactory.createTitledBorder("Routine Services"));
    topPanel.add(oil);
    topPanel.add(lube);
    topPanel.add(radiator);
    topPanel.add(trans);
    topPanel.add(inspect);
    topPanel.add(muffler);
    topPanel.add(tire);

    messageLabel1 = new JLabel("Parts charges:");
    autoTextField1 = new JTextField(10);
    messageLabel2 = new JLabel("Hours of Labor:");
    autoTextField2 = new JTextField(10);
    calcButton = new JButton("Calculate");
    calcButton.addActionListener(new CalcButtonListener());
    exitButton = new JButton("Exit");
    exitButton.addActionListener(new exitButtonListener());

    centerPanel = new JPanel();
    centerPanel.setBorder(BorderFactory.createTitledBorder("Nonroutine Services"));
    centerPanel.add(messageLabel1);
    centerPanel.add(autoTextField1);
    centerPanel.add(messageLabel2);
    centerPanel.add(autoTextField2);
    centerPanel.add(calcButton);
    centerPanel.add(exitButton);
}
private class CalcButtonListener implements ActionListener {
    public void actionPerformed(ActionEvent e){
        String input, input2;
        double parts, hours, labor;
        double grandTotal = 0;

        if ( oil.isSelected()){
            grandTotal += 26;
        }
        if ( lube.isSelected()){
            grandTotal += 18;
        }
        if ( radiator.isSelected()){
            grandTotal += 30;
        }
        if ( trans.isSelected()){
            grandTotal += 80;
        }
        if ( inspect.isSelected()){
            grandTotal += 15;
        }
        if ( muffler.isSelected()){
            grandTotal += 100;
        }
        if ( tire.isSelected()){
            grandTotal += 20;
        }
        {
            input = autoTextField1.getText();
            parts = Double.parseDouble(input);
            input2 = autoTextField2.getText();
            hours = Double.parseDouble(input2);
            labor = hours * 20;
            grandTotal += parts + labor;
        }

        JOptionPane.showMessageDialog(null, "Total Charges: $" + grandTotal );
    }
}
private class exitButtonListener implements ActionListener {
    public void actionPerformed(ActionEvent e){
        dispose();
    }
}

}

继承运行它的代码：

//Programmer: Davis Bentley
//Date: 10/21/2015
//Purpose: To allow user to calculate auto service cost

public class autoRun {

public static void main(String[] args) {
    autoCalc auto = new autoCalc();
}

}

Answer 1

frame.add(topPanel);
frame.add(centerPanel);
topPanel = new JPanel();

有几个问题：

当您尝试将topPanel和centerPanel变量添加到框架时，它们为null，因此您实际上不向框架添加任何内容。创建面板，向面板添加组件，然后将面板添加到框架中。
JFrame的默认布局管理器是BorderLayout。向框架添加组件并且未指定约束时，两个组件都将添加到CENTER中。但是，中心只能显示一个组件。

尝试：

frame.add(topPanel, BorderLayout.PAGE_START);
frame.add(centerPanel, BorderLayout.CENTER);

并将这些陈述移至buildPanel()方法的底部。

阅读Using Layout Managers上Swing教程中的部分，了解更多信息和工作示例。

保留教程的链接，以便学习Swing基础知识。

如何使用两个标题边框围绕单独的组件？

1 个答案: