Question

所以我一直在为我的大学课程制作这个GUI温度转换器，我差不多完成了但我无法弄清楚为什么我无法通过按钮btnCalc来显示不同复选框的结果。如果我这样做，它会显示一些东西

if(ae.getSource()==btnCalc) JOptionPane.showMessageDialog(this,"Button");

无论如何，如果想出这个，我真的很感激任何帮助。我只是希望程序在点击计算按钮后显示结果。

package TempConverter;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JOptionPane;

/**
 *
 * @author 00220682
 */
public class TempConvertGUI extends javax.swing.JFrame implements ActionListener{


public TempConvertGUI() {
    initComponents();
    btnCalc.addActionListener(this);
    degrees.addActionListener(this);
    CtoF.addActionListener(this);
    FtoC.addActionListener(this);
}

/**
 * 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() {

    buttonGroup1 = new javax.swing.ButtonGroup();
    jLabel1 = new javax.swing.JLabel();
    degrees = new javax.swing.JTextField();
    btnCalc = new javax.swing.JButton();
    lblResults = new javax.swing.JLabel();
    jLabel2 = new javax.swing.JLabel();
    CtoF = new javax.swing.JCheckBox();
    FtoC = new javax.swing.JCheckBox();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
    setTitle("Temperate Converter");

    jLabel1.setText("Enter The Degrees:");

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

    btnCalc.setText("Calculate");
    btnCalc.addMouseListener(new java.awt.event.MouseAdapter() {
        public void mouseClicked(java.awt.event.MouseEvent evt) {
            btnCalcMouseClicked(evt);
        }
    });
    btnCalc.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            btnCalcActionPerformed(evt);
        }
    });

    jLabel2.setText("What would you like to convert?");

    buttonGroup1.add(CtoF);
    CtoF.setText("Celcius to Fahrenheit");
    CtoF.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            CtoFActionPerformed(evt);
        }
    });

    buttonGroup1.add(FtoC);
    FtoC.setText("Fahrenheit to Celcius");
    FtoC.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            FtoCActionPerformed(evt);
        }
    });

    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()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addGroup(layout.createSequentialGroup()
                            .addComponent(jLabel1)
                            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                            .addComponent(degrees, javax.swing.GroupLayout.PREFERRED_SIZE, 226, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                            .addComponent(btnCalc, javax.swing.GroupLayout.PREFERRED_SIZE, 258, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                                .addGroup(layout.createSequentialGroup()
                                    .addComponent(FtoC)
                                    .addGap(32, 32, 32)
                                    .addComponent(CtoF))
                                .addGroup(layout.createSequentialGroup()
                                    .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 226, javax.swing.GroupLayout.PREFERRED_SIZE)
                                    .addGap(60, 60, 60)))))
                    .addGap(0, 0, Short.MAX_VALUE))
                .addComponent(lblResults, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
            .addContainerGap())
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jLabel1)
                .addComponent(degrees, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
            .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 31, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(FtoC)
                .addComponent(CtoF))
            .addGap(18, 18, 18)
            .addComponent(btnCalc, javax.swing.GroupLayout.PREFERRED_SIZE, 47, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
            .addComponent(lblResults, javax.swing.GroupLayout.PREFERRED_SIZE, 64, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
    );

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

private void degreesActionPerformed(java.awt.event.ActionEvent evt) {                                        
     CtoF.setEnabled(true);
     FtoC.setEnabled(true);
}                                       

private void FtoCActionPerformed(java.awt.event.ActionEvent evt) {                                     

}                                    

private void CtoFActionPerformed(java.awt.event.ActionEvent evt) {                                     

}                                    

private void btnCalcMouseClicked(java.awt.event.MouseEvent evt) {                                     

}                                    

private void btnCalcActionPerformed(java.awt.event.ActionEvent evt) {                                        
    // TODO add your handling code here:
}                                       

/**
 * @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(TempConvertGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(TempConvertGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(TempConvertGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(TempConvertGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>
    //</editor-fold>

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new TempConvertGUI().setVisible(true);
            CtoF.setEnabled(false);
            FtoC.setEnabled(false);

        }
    });
}

// Variables declaration - do not modify                     
public static javax.swing.JCheckBox CtoF;
public static javax.swing.JCheckBox FtoC;
static javax.swing.JButton btnCalc;
private javax.swing.ButtonGroup buttonGroup1;
public static javax.swing.JTextField degrees;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel lblResults;
// End of variables declaration                   

@Override
public void actionPerformed(ActionEvent ae) {

     double display = 0;
     double x = 0;
     CtoF DegreesC = new CtoF(0);
     FtoC DegreesF = new FtoC(0);



     if(ae.getSource()==CtoF){
            double DinC = Double.parseDouble(degrees.getText());
            DegreesC.setDegrees(DinC);
            display = DegreesC.CtoFconvert();
            x = 1;
     }
     else if (ae.getSource()==FtoC){
            double DinF = Double.parseDouble(degrees.getText());
            DegreesF.setDegrees(DinF);
            display = DegreesF.FtoCconvert();
            x = 2;
     }

     if (ae.getSource() == btnCalc){

            if (x == 1){
                lblResults.setText("<html>Degrees in Celcius: " + degrees.getText() + "<br>Degrees in Fahrenheit: " + display);
            }
            else if (x == 2){
                lblResults.setText("<html>Degrees in Fahrenheit: " + degrees.getText() + "<br>Degrees in Celcius: " + display);
            }         



  }


}

}

Answer 1

我不确定我是否完全理解这个问题，但看看这是否有帮助...

您在复选框和计算按钮上使用相同的ActionListener。您的构造函数使用

初始化它们

btnCalc.addActionListener(this);
degrees.addActionListener(this);
CtoF.addActionListener(this);
FtoC.addActionListener(this);

因此，当按下任何一个时，该动作监听器将触发。添加多个更小，更具体的动作侦听器而不是一个必须检查源的大型侦听器可能更有意义。因此，btnCalc的动作侦听器将显示结果，其他每个按钮都有自己的动作侦听器，用于设置需要设置的变量。

Java GUI actionPerformed（）问题

1 个答案: