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我一直在這一段時間，但我似乎無法修復給我所有問題的一條線。這一行「list = new JComboBox（measure）;」在陣列下面，似乎給了我錯誤。我可以抑制錯誤，它運行除了JComboBox無法正常工作，並給出錯誤 「線程中的異常」AWT-EventQueue-0「java.lang.ClassCastException：javax.swing.JComboBox不能轉換爲javax.swing。 JButton at cube.actionPerformed（cube.java:132）「問題與數組填充JComboBox
任何幫助將不勝感激！
import java.util.Scanner;
import javax.swing.*;
import java.awt.*;
import java.net.*;
import java.awt.event.*;
//@SuppressWarnings("unchecked")
public class cube extends JFrame implements ActionListener{
public static JComboBox list;
public static JTextField a;
public static JTextField b;
public static JTextField c;
public static JTextField d;
public static String measureFinal;
public static String measurement;
//public static String [] measurement = {"Inches" , "Meters", "Feet" , "Centimeters" , "Millimeters" , "Yards" };
public static JFrame main = new JFrame("Volume of Cube");
public static JPanel myPanel = new JPanel(new GridLayout (0,1));
public static void main(String args[]){
cube object = new cube();
}
cube(){
main.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
myPanel.setPreferredSize(new Dimension(400,350));
main.add(myPanel);
a = new JTextField(3);
b = new JTextField(3);
c = new JTextField(3);
d = new JTextField(3);
JButton button1 = new JButton("Solve!");
JButton button2 = new JButton("Back to shape selector");
myPanel.add(new JLabel ("Select the unit of measurement"));
String measure[] = {"Inches" , "Meters", "Feet" , "Centimeters" , "Millimeters" , "Yards" };
list = new JComboBox(measure);
list.setSelectedIndex(0);
list.addActionListener(this);
myPanel.add(list);
myPanel.add(new JLabel ("Enter the height of the box"));
myPanel.add(a);
myPanel.add(new JLabel ("Enter the width of the box"));
myPanel.add(b);
myPanel.add(new JLabel ("Enter the length of the box"));
myPanel.add(c);
myPanel.add(button1);
button1.addActionListener(this);
myPanel.add(button2);
button2.addActionListener(this);
main.pack();
main.setLocation(600,200);
main.setVisible(true);
//tring [] measurement = {"Inches" , "Meters", "Feet"};
//double volume = height * width * length;
//String answer = "The volume of the box is " +volume+ measurement;
}
public void CBSelect(ActionEvent e){
int temp = 0;
temp = list.getSelectedIndex();
//Object temp = e.getSource();
/*
if (e.getSource() == list){
temp = list.getSelectedIndex();
switch(temp){
case 0:
measurement = "Inches";
break;
case 1:
measurement = "Meters";
break;
case 2:
measurement = "Feet";
break;
case 3:
measurement = "Centimeters";
break;
case 4:
measurement = "Millimeters";
break;
case 5:
measurement = "Yards";
break;
}
}
*/
if (temp == 0){
measurement = "Inches";
} else if (temp == 1){
measurement = "Meters";
}else if (temp == 2){
measurement = "Feet";
}else if (temp == 3){
measurement = "Centimeters";
}else if (temp == 4){
measurement = "Millimeters";
}else if (temp == 5){
measurement = "Yards";
}
}
public void actionPerformed(ActionEvent e) {
String actionCommand = ((JButton) e.getSource()).getActionCommand();
//JComboBox cb = ((JComboBox) e.getSource());
//measureFinal = (String)cb.getSelectedItem();
if (actionCommand == "Solve!"){
double height = Double.parseDouble(a.getText());
double width = Double.parseDouble(b.getText());
double length = Double.parseDouble(c.getText());
double volume = height * width * length;
try{
final ImageIcon icon = new ImageIcon(new URL("http://wiki.fantasticcontraption.com/w/images/0/06/Solved.png"));
JOptionPane.showMessageDialog(this, ("The volume of the box is " +volume+" "+ measurement),"Volume", JOptionPane.PLAIN_MESSAGE, icon);
} catch (MalformedURLException ex){
System.out.println("Image Not Found!");
}
}
if (actionCommand == "Back to shape selector"){
main.dispose();
main.setVisible(false);
}
}
}
UPDATE：回過頭來看，現在我想問題出在CBSelect動作偵聽器內。
如果我取消註釋測量的第二個定義 - 那麼我會從第94行開始標記錯誤。度量定義爲String []，您試圖將其設置爲String。我會從那裏開始。我會查看代碼，看看我能否弄清楚你正在做什麼。 – mikemil