Question

我正在尝试在JAVA中的类中实现一个类，比如

package test;
import java.awt.event.*;
import javax.swing.*;
/**
 *
 * @author jackandjill
 */
public class Summingup extends JFrame {

    /**
     * Creates new form Summingup
     */
    public Summingup() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        input1_tb = new javax.swing.JTextField();
        calculate_btn = new javax.swing.JButton();
        result_lbl = new javax.swing.JLabel();
        input2_tb = new javax.swing.JTextField();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jLabel1.setText("Input 1");

        jLabel2.setText("Input 2");

        calculate_btn.setText("SUM");

        result_lbl.setText("RESULT DISPLAYED HERE!");

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addComponent(jLabel1)
                        .addGap(18, 18, 18)
                        .addComponent(input1_tb))
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addComponent(jLabel2)
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(jPanel1Layout.createSequentialGroup()
                                .addGap(18, 18, 18)
                                .addComponent(result_lbl))
                            .addGroup(jPanel1Layout.createSequentialGroup()
                                .addGap(18, 18, 18)
                                .addComponent(input2_tb)))))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(calculate_btn)
                .addContainerGap())
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addGap(1, 1, 1)
                        .addComponent(calculate_btn, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jLabel1)
                            .addComponent(input1_tb, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jLabel2)
                            .addComponent(input2_tb, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 20, Short.MAX_VALUE)
                .addComponent(result_lbl)
                .addContainerGap())
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /*
         * Set the Nimbus look and feel
         */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /*
         * If Nimbus (introduced in Java SE 6) is not available, stay with the
         * default look and feel. For details see
         * http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(Summingup.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Summingup.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Summingup.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Summingup.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /*
         * Create and display the form
         */
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                new Summingup().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JButton calculate_btn;
    private javax.swing.JTextField input1_tb;
    private javax.swing.JTextField input2_tb;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JLabel result_lbl;
    // End of variables declaration
}

class InvalidValueException implements ActionListener
{
    public void actionPerformed(ActionEvent ae)
    {
         try
       {
           if(ae.getSource() ==calculate_btn)
           {
               String input_1 = input1_tb.getText();
                String input_2 = input2_tb.getText();

                checkBlanklnput(input_1,input_2);

                validateInput(Integer.parseInt(input_1),Integer.parseInt(input_2));

                result_lbl.setText(calculate(Integer.parseInt(input_1),Integer.parseInt(input_2)));

           }
       }

       catch (NumberFormatException excep)
       {
        result_lbl.setText("Invalid number");
       }
       catch (InvalidInputException excep)
       {
         result_lbl.setText(excep.getMessage());
       }
       catch (BlankInputException excep)
       {
         result_lbl.setText(excep.getMessage());
       }

    }



    public void checkBlanklnput(String input1,String input2) throws BlanklnputException 
    {
        if (input1.length() == 0 ||input2.length() == 0) throw new BlanklnputException();
    }

    public void validateInput(int input1 , int input2) throws InvalidInputException
    {

        if (input1 + input2 > 100 )
        throw new InvalidInputException();
    }

    public String calculate(int input1, int input2)
    {
        String res = "";
        while (true) 
        {
            res = Integer.toString(input1 + input2);
            break;
        }
        return res;

    }

}

class InvalidInputException extends Exception {

public InvalidInputException() {

super("Invalid number");

}
}
class BlankInputException extends Exception {

public BlankInputException() {

super("Input cannot be blank");

} 
 }

所以这个类也抛出很多异常并捕获它们。但唯一的问题是 InvalidValueException 类中无法识别JForm控件。不知道如何打开这个控件到这个类。

我面临的另一个问题是我的validateInput正在检查最大总和但我想检查IF是否在文本框中输入了除数字之外的任何字母。

这就是我的GUI看起来像

enter image description here

Answer 1

您可以将您的实施与显示的here工作示例进行比较。它使用JFormattedTextField来强制执行数字输入，以及PropertyChangeListener＆amp; FocusListener更新总和。

顺便说一句，在过度依赖GUI编辑器之前，你应该学习layouts。另请参阅Nested Classes。

附录：BlankInputException拼写错误，你的（名字奇怪的）ActionListener未被使用。您应该能够使用自定义代码属性对其进行初始化。

calculate_btn.addActionListener(new InvalidValueException());

在课堂上实施一个班级

1 个答案: