java - 我的 ButtonListener Dial 程序出现错误

Question

我只是想找出为什么会出现这些错误。我不太清楚为什么它说找不到变量或者为什么它不允许我添加或减去一个 int 。

错误如下:

         javac Dial2.java
 Dial2.java:53: cannot find symbol
symbol  : class arrl
location: class DialFrame
b.addActionListener(new arrl());
                        ^
Dial2.java:56: b is already defined in DialFrame(java.lang.String)
Button b = new Button("<");
       ^
Dial2.java:57: cannot find symbol
symbol  : class arrl
location: class DialFrame
b.addActionListener(new arrl());
                        ^
Dial2.java:127: cannot find symbol
symbol  : variable pastNumbeCount
location: class DialFrame.ArrowListener
    arrowIndex = (arrowIndex + pastNumbeCount - 1) % pastNumberCount;
                               ^
Dial2.java:127: operator + cannot be applied to int,pastNumbeCount
    arrowIndex = (arrowIndex + pastNumbeCount - 1) % pastNumberCount;
                  ^
Dial2.java:127: operator - cannot be applied to <nulltype>,int
    arrowIndex = (arrowIndex + pastNumbeCount - 1) % pastNumberCount;
                                              ^
Dial2.java:128: cannot find symbol
symbol  : variable arrowindex
location: class DialFrame.ArrowListener
    phoneNumber.setText(pastNumbers[arrowindex - 1]);
                                    ^
Dial2.java:133: cannot find symbol
symbol  : variable pastNumberindex
location: class DialFrame.ArrowListener
    phoneNumber.setText(pastNumberindex);
                        ^
8 errors

这是一个简单的电话拨号器的代码:

cat Dial2.java
import java.awt.*;
import java.awt.event.*;

// Driver class
public class Dial2 {

public static void main(String[] args) {
Frame frame = new DialFrame("Dial");
frame.pack();
frame.setVisible(true);
}
}

// Frame class
class DialFrame extends Frame {
private TextField phoneNumber = new TextField();
private String pastNumbers[] = new String[10];
private int pastNumberCount = 0;
private int pastNumberIndex = 0;
private int arrowIndex = 0;

// Constructor
public DialFrame(String title) {
// Set title
super(title);

// set all pastNumbers to empty string
for (int x = 0; x < pastNumbers.length; x++)
  pastNumbers[x] = "";

// Make text field non-editable and put at top of frame
phoneNumber.setEditable(false);
add("North", phoneNumber);

// Create panel to hold buttons and set its layout
Panel buttonPanel = new Panel();
buttonPanel.setLayout(new GridLayout(4, 3, 10, 10));

DigitListener dl = new DigitListener();
ArrowListener arrl = new ArrowListener();

// Create first nine buttons, attach a listener to each,
// and add buttons to buttonPanel
for (int i = 1; i <= 9; i++) {
  Button b = new Button(i + "");
  b.addActionListener(dl);
  buttonPanel.add(b);
}

// **1** Add your two new buttons to your panel, along with an
//       an arrow listener for both
Button b = new Button(">");
b.addActionListener(new arrl());

b = new Button("0");
Button b = new Button("<");
b.addActionListener(new arrl());
buttonPanel.add(b);



// Create a panel to hold buttonPanel; put it at the
// center of the frame
Panel centerPanel = new Panel();
centerPanel.add(buttonPanel);
add("Center", centerPanel);

// Create a panel to hold the "Dial" button; put it at
// the bottom of the frame
Panel bottomPanel = new Panel();
b = new Button("Dial");
b.addActionListener(new DialListener());
bottomPanel.add(b);
add("South", bottomPanel);

// Attach window listener
addWindowListener(new WindowCloser());
}

private void addPastNumber(String num) {
boolean numberAlreadyAdded = false;
for (int x=0; x < pastNumbers.length; x++) {
  if (pastNumbers[x].equals(num)) {
    numberAlreadyAdded = true;  break;
  }
}
if (!numberAlreadyAdded) {
  pastNumbers[pastNumberIndex] = num;
  pastNumberIndex++;
  if (pastNumberCount < 10) pastNumberCount++;
  if (pastNumberIndex == pastNumbers.length) pastNumberIndex = 0;
}
arrowIndex = pastNumberIndex;
}  

 // Listener for all buttons
class DigitListener implements ActionListener {
public void actionPerformed(ActionEvent evt) {
  String buttonLabel = evt.getActionCommand();
  // append the digit on the newly pressed key
  phoneNumber.setText(phoneNumber.getText() + buttonLabel);
}
}

// Listener for all buttons
class DialListener implements ActionListener {
public void actionPerformed(ActionEvent evt) {
  addPastNumber(phoneNumber.getText());
  phoneNumber.setText("Dialing...");
  // pause for two seconds, or 2000 millisecond  
  try {
    Thread.sleep(2000);
  } catch (InterruptedException e) {}
  phoneNumber.setText("");
}
}

// Listener for "arrow" buttons
class ArrowListener implements ActionListener {
public void actionPerformed(ActionEvent evt) {

  // ** 2 **
String buttonLabel = evt.getActionCommand();

if (buttonLabel == "<")
{
    arrowIndex = (arrowIndex + pastNumbeCount - 1) % pastNumberCount;
    phoneNumber.setText(pastNumbers[arrowindex - 1]);
}
else
{
    arrowIndex = (arrowIndex + 1) % pastNumberCount;
    phoneNumber.setText(pastNumberindex);
}








}
}

 // Listener for window
class WindowCloser extends WindowAdapter {
public void windowClosing(WindowEvent evt) {
  System.exit(0);
}
}
}

任何帮助或信息将不胜感激。

说明:如果 PastNumbers 数组中的当前索引为 9，则按下“>”键将显示索引 0 处存储的数字。如果当前索引为 0，则按“<”键将显示索引 9 处存储的数字。

要进行此设置，我需要从按钮中检索标签。如果是“<”键，请将我的箭头索引设置为: (arrowIndex + 过去的数字计数 - 1) % 过去的数字计数;并将过去号码数组中该索引处的过去号码添加到我的电话号码文本字段中。

否则，我需要将数组索引设置为:(arrowIndex + 1) % pastNumberCount，并将该索引处的过去数字添加到文本字段中。

Answer 1

使用new ArrowListener()代替new arl()； (arrl 不是一个类，它是一个对象)使用 PastNumberCount 而不是 PastNumbeCount (r 缺失)使用 arrowIndex 代替 arrowindex (i 应该大写)使用过去编号索引而不是过去编号索引(i应该是大写)

你的程序中有很多错别字。

问候，亚什