Question

这是我当前的代码，showButton现在正在运行，感谢你，但不幸的是，totalButton仍然没有。你能帮我搞清楚吗？

 import java.awt.*;
 import java.awt.event.*;
 import javax.swing.*;
import javax.swing.JButton;
import javax.swing.JTextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import java.util.EventObject;

public class GUISS extends JFrame implements ActionListener
{

public static void main(String[] args)
{
new GUISS();
}
private JButton totalButton, showButton;
private JTextField productField,  productField2, productField3, productField4, productField5;
private JTextField priceField, priceField2, priceField3, priceField4, priceField5;
private JTextField quantityField, quantityField2, quantityField3, quantityField4, quantityField5;
private JTextField totalField, totalField2, totalField3, totalField4, totalField5, emptyField, totalAmountField;
static double num1 , num2, num3, num4, num5, ans, ans2;
static double CBOX1 = 25.00, CBOX2 = 25.00, CBOX3 = 39.00, CBOX4 = 25.00;

public GUISS()
{
    setLayout(new FlowLayout());
    setTitle("Mcdonalds");
    setSize(520,200);

    productField = new JTextField("Best Sellers", 10);
    productField. setEditable(false);

    productField2 = new JTextField("Burger Mcdo", 10);
    productField2.setEditable(false);

    productField3 = new JTextField("Hot Fudge Sundae", 10);
    productField3.setEditable(false);

    productField4 = new JTextField("CheeseBurger", 10);
    productField4.setEditable(false);

    productField5 = new JTextField("Regular McFries", 10);
    productField5.setEditable(false);

    priceField = new JTextField("Alacarte Price", 10);
    priceField.setEditable(false);

    priceField2 = new JTextField("P25.00", 10);
    priceField2.setEditable(false);

    priceField3 = new JTextField("P25.00", 10);
    priceField3.setEditable(false);

    priceField4 = new JTextField("P39.00", 10);
    priceField4.setEditable(false);

    priceField5 = new JTextField("P25.00", 10);
    priceField5.setEditable(false);





    quantityField = new JTextField("Quantity", 10);
    quantityField.setEditable(false);

    quantityField2 = new JTextField(10);

    quantityField3 = new JTextField(10);

    quantityField4 = new JTextField(10);

    quantityField5 = new JTextField(10);


    totalField = new JTextField("Total Price", 10);
    totalField.setEditable(false);

    totalField2 = new JTextField("P0.0", 10);
    totalField2.setEditable(false);

    totalField3 = new JTextField("P0.0", 10); 
    totalField3.setEditable(false);

    totalField4 = new JTextField("P0.0", 10);
    totalField4.setEditable(false);

    totalField5 = new JTextField("P0.0", 10);
    totalField5.setEditable(false);

    emptyField = new JTextField(10);
   // JButton showButton = new JButton("Show price");
    //JTextFieldtotalButton = new JButton("Total Amount");
    totalAmountField = new JTextField("P0.0", 10);
    totalAmountField.setEditable(false);
  JTextField CashField = new JTextField(10);


 totalButton = new JButton("Total Amount");
  showButton = new JButton("Show price");

    add(productField);
    add(priceField);
    add(quantityField);
    add(totalField);

    add(productField2);
    add(priceField2);
    add(quantityField2);
    add(totalField2);

    add(productField3);
    add(priceField3);
    add(quantityField3);
    add(totalField3);

    add(productField4);
    add(priceField4);
    add(quantityField4);
    add(totalField4);

    add(productField5);
    add(priceField5);
    add(quantityField5);
    add(totalField5);

    add(showButton);
    showButton.addActionListener(this);
    add(totalButton);
    totalButton.addActionListener(this);
    add(totalAmountField);
    setVisible(true);




    }

    public void actionPerformed ( ActionEvent e )
    {  

     System.out.println("Entered action performed");

    if(e.getSource() == showButton ){
        if(!quantityField2.getText().equals(emptyField.getText())){
            num1 = Double.parseDouble(String.valueOf(quantityField2.getText()));
            ans = num1 * CBOX1 ;
            totalField2.setText(String.valueOf("P" + ans));
        }
        if(!quantityField3.getText().equals(emptyField.getText())){
            num1 = Double.parseDouble(String.valueOf(quantityField3.getText()));
            ans = num1 * CBOX2 ;
            totalField3.setText(String.valueOf("P" + ans));
        }
        if(!quantityField4.getText().equals(emptyField.getText())){
            num1 = Double.parseDouble(String.valueOf(quantityField4.getText()));
            ans = num1 * CBOX3 ;
            totalField4.setText(String.valueOf("P" + ans));
        }
        if(!quantityField5.getText().equals(emptyField.getText())){
            num1 = Double.parseDouble(String.valueOf(quantityField5.getText()));
            ans = num1 * CBOX4 ;
            totalField5.setText(String.valueOf("P" + ans));
       }           
        else if(e.getSource() == totalButton){
        if(!totalField2.getText().equals(0)){
            num2 = Double.parseDouble(String.valueOf(totalField2.getText()));
        }
        if(!totalField3.getText().equals(0)){
            num3 = Double.parseDouble(String.valueOf(totalField3.getText()));
        }
        if(!totalField4.getText().equals(0)){
            num4 = Double.parseDouble(String.valueOf(totalField4.getText()));
        }
        if(!totalField5.getText().equals(0)){
            num5 = Double.parseDouble(String.valueOf(totalField5.getText()));
        }
        else {
        ans2 = num2 + num3 + num4 + num5 ;

        totalAmountField.setText(String.valueOf("P" + ans2));
    }
}
    }
}
}

感谢您的帮助，这段代码对我来说非常重要

Answer 1

这里的问题是你没有向按钮添加一个动作监听器来监听由名为showButton的按钮触发的事件。添加按钮后，您需要在代码中添加以下内容。

public GUISS()
{
    ...//your code as is
    add(showButton);
    showButton.addActionListener(this);
    ...//the rest of your code as is
}

另外，为了确保您输入actionPerformed方法，请尝试在方法开头打印一些内容并查看它是否输出到控制台。我添加的代码行是将actionListener添加到GUISS的当前实例。这意味着您创建GUISS的实例将侦听按钮showButton执行的操作。有关详细信息，请查看链接http://docs.oracle.com/javase/tutorial/uiswing/events/actionlistener.html

这里的另一个问题是你正在创建一个名为showButton的局部变量，并且该操作被添加到实例变量showButton的按钮，以解决此问题修改代码如下所示：

public GUISS() {
    //JButton showButton = new JButton("Show price"); 
}

基本上注释掉名为showButton的局部变量。如果没有对此行进行注释，则getSource的if条件将不会给出实例变量，因此它们将不相等。

最后你有关于totalButton条件的错误，如果e.getSource（）== totalButton被置于e.getSource（）== showButton的条件内，则totalButton条件因此它永远不会被执行你应该重新考虑else if if if if e.getSource（）== showButton

方法actionPerformed不起作用

1 个答案: