Question

这是我的代码几乎按预期工作。在我遇到问题之前，请查看代码，请原谅我的长代码，但这可以像java类一样粘贴，我使用NETBEANS JForm设计器来获取GUI。

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.
     */

    // <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");
        calculate_btn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                calculate_btnActionPerformed(evt);
            }
        });

        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>                        

    private void calculate_btnActionPerformed(java.awt.event.ActionEvent evt) {                                              
        // TODO add your handling code here:
        InvalidValueException ive = new InvalidValueException();
        calculate_btn.addActionListener(ive);
        //addActionListener
    }                                             

    /**
     * @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                     
    public javax.swing.JButton calculate_btn;
    public javax.swing.JTextField input1_tb;
    public javax.swing.JTextField input2_tb;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    public javax.swing.JPanel jPanel1;
    public 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();

                checkBlankInput(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 (BlankInputException excep)
       {
         result_lbl.setText(excep.getMessage());
       }
         catch (InvalidInputException excep)
       {
         result_lbl.setText(excep.getMessage());
       }
    }



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

    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");

} 
 }

因此，让我简要介绍一下代码，这段代码基本上是初始化一个GUI并进行大量的异常处理，确实很重要，你可以看到整个代码，这样你就可以更清楚地理解并准确回答。这是我执行程序时得到的布局

enter image description here

所以在我按下SUM按钮 ONE 时间

之后

仍然与上面相同的图像没有变化

我再次按下SUM按钮。第二次

enter image description here

所以希望你看到了！文本字段的长度越来越短了吗？甚至不知道从哪里开始，如果你打算让我做调试，我已经做了但是它仍然没有做任何尺寸减少什么呢？

Answer 1

文本字段的长度越来越短，因为result_lbl标签中的文字会随着单击按钮时的更改而变短。您会注意到文本字段的长度始终与下面标签的长度相同。

要修复它，只需构造具有指定列数的文本字段，例如

    input1_tb = new JTextField(20);

因此，无论下面的标签发生什么，文本字段的长度都不应受到影响。

编辑：

why doesn't the button listener is not kicking in the first time?

删除此

    calculate_btn.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            calculate_btnActionPerformed(evt);
        }
    });

和这个

private void calculate_btnActionPerformed(java.awt.event.ActionEvent evt) {                                              
    // TODO add your handling code here:
    InvalidValueException ive = new InvalidValueException();
    calculate_btn.addActionListener(ive);
    //addActionListener
}

并用这一行替换它们：

    calculate_btn.addActionListener(new InvalidValueException());

创建按钮后

Answer 2

文本字段添加在带有结果标签的同一垂直列上。当结果标签更改其大小时，它也会影响文本字段。

我在代码中注意到的另一个奇怪的事情是，只要您处理已注册的InvalidValueException，就会将ActionListener添加为按钮ActionListener。你应该这样做一次而不是按下按钮。

无法找到布局变小的原因

2 个答案: