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我正在構建幾何計算器的過程中，但我很難實現ActionListener。我在Oracle網站上找到了一些示例代碼，並對其進行了修改以適應我正在嘗試執行的視覺概念。使用ActionListener輸出幾何計算器的計算結果
我梳理了我的代碼尋找錯別字和不正確的標點符號，並糾正它或沒有發現任何東西卡住了我。我查看了Stack Overflow和課本中的類似問題，並且我的代碼在結構上看起來與示例中正在做的類似。我粘貼了以下代碼的相關部分。
Eclipse給我這個錯誤信息：線程「AWT-EventQueue-0」中的異常java.lang.Error：未解決的編譯問題： CalcButtonListenerA無法解析爲類型我不明白爲什麼會發生這種情況。我想這些線路將採取解決類型的護理：
`calcButton1 = new JButton("Calculate");
calcButton1.addActionListener(new CalcButtonListenerA());`
其他相關的代碼如下...
package layout;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class GeometryCalculator implements ItemListener {
JPanel calcTools;
final static String CIRCLEPANEL = "Circle Calculator";
final static String RECTANGLEPANEL = "Rectangle Calculator";
final static String TRIANGLEPANEL = "Triangle Calculator";
private JLabel messageLabel1;
private JLabel messageLabel2;
private JLabel messageLabel3;
private JLabel radiusLabel;
private JLabel baseLabel;
private JLabel heightLabel;
private JLabel lengthLabel;
private JLabel widthLabel;
private JLabel circleAreaLabel;
private JLabel circumferenceLabel;
private JLabel rectanglePerimeterLabel;
private JLabel rectangleAreaLabel;
private JLabel triangleAreaLabel;
private JTextField choiceTextField;
private JTextField radiusTextField;
private JTextField baseTextField;
private JTextField heightTextField;
private JTextField lengthTextField;
private JTextField widthTextField;
private JButton calcButton1;
private JButton calcButton2;
private JButton calcButton3;
JTextField rectanglePerimeterField = new JTextField(15);
JTextField rectangleAreaField = new JTextField(15);
JTextField triangleAreaField = new JTextField(15);
public void addComponentToPane(Container pane) {
JPanel comboBoxPane = new JPanel();
String comboBoxItems[] = { CIRCLEPANEL, RECTANGLEPANEL, TRIANGLEPANEL };
JComboBox cb = new JComboBox(comboBoxItems);
cb.setEditable(false);
cb.addItemListener(this);
comboBoxPane.add(cb);
//Create the "calcTools".
JPanel calcTool1 = new JPanel();
radiusLabel = new JLabel("Radius");
circumferenceLabel = new JLabel("Circumference");
circleAreaLabel = new JLabel("Area");
radiusTextField= new JTextField(10);
messageLabel1 = new JLabel("Let's make some circle calculations.");
final JTextField circumferenceField = new JTextField(15);
circumferenceField.setEditable(false);
final JTextField circleAreaField = new JTextField(15);
circleAreaField.setEditable(false);
calcButton1 = new JButton("Calculate");
calcButton1.addActionListener(new CalcButtonListenerA());
calcTool1.add(messageLabel1);
calcTool1.add(radiusLabel);
calcTool1.add(radiusTextField);
calcTool1.add(circumferenceLabel);
calcTool1.add(circumferenceField);
calcTool1.add(circleAreaLabel);
calcTool1.add(circleAreaField);
calcTool1.add(calcButton1);
class CalcButtonListenerA implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String radius;
double circumference;
double circleArea;
radius = radiusTextField.getText();
circumference = 2*Double.parseDouble(radius)*Math.PI;
String circ = String.valueOf(circumference);
circleArea = Double.parseDouble(radius)* Double.parseDouble(radius)*Math.PI;
String area = String.valueOf(circleArea);
circumferenceField.setText(circ);
circleAreaField.setText(area);
}
}
JPanel calcTool2 = new JPanel();
messageLabel2 = new JLabel("Let's make some rectangle calculations.");
lengthLabel = new JLabel("Length");
widthLabel = new JLabel("Width");
lengthTextField = new JTextField(10);
widthTextField = new JTextField(10);
rectanglePerimeterLabel = new JLabel("Perimeter");
rectangleAreaLabel = new JLabel("Area");
JTextField rectanglePerimeterField = new JTextField(15);
rectanglePerimeterField.setEditable(false);
JTextField rectangleAreaField = new JTextField(15);
rectangleAreaField.setEditable(false);
JButton calcButton2 = new JButton("Calculate");
calcTool2.add(messageLabel2);
calcTool2.add(lengthLabel);
calcTool2.add(lengthTextField);
calcTool2.add(widthLabel);
calcTool2.add(widthTextField);
calcTool2.add(rectanglePerimeterLabel);
calcTool2.add(rectanglePerimeterField);
calcTool2.add(rectangleAreaLabel);
calcTool2.add(rectangleAreaField);
calcTool2.add(calcButton2);
JPanel calcTool3 = new JPanel();
messageLabel3 = new JLabel("Let's make some triangle calculations");
baseLabel = new JLabel("Base");
heightLabel = new JLabel("Height");
baseTextField = new JTextField(10);
heightTextField = new JTextField(10);
triangleAreaLabel = new JLabel("Area");
triangleAreaField = new JTextField(15);
triangleAreaField.setEditable(false);
JButton calcButton3 = new JButton("calculate");
calcTool3.add(messageLabel3);
calcTool3.add(baseLabel);
calcTool3.add(baseTextField);
calcTool3.add(heightLabel);
calcTool3.add(heightTextField);
calcTool3.add(triangleAreaLabel);
calcTool3.add(triangleAreaField);
calcTool3.add(calcButton3);
calcTools = new JPanel(new CardLayout());
calcTools.add(calcTool1, CIRCLEPANEL);
calcTools.add(calcTool2, RECTANGLEPANEL);
calcTools.add(calcTool3, TRIANGLEPANEL);
pane.add(comboBoxPane, BorderLayout.PAGE_START);
pane.add(calcTools, BorderLayout.CENTER);
}
public void itemStateChanged(ItemEvent evt) {
CardLayout cl = (CardLayout)(calcTools.getLayout());
cl.show(calcTools, (String)evt.getItem());
}
private static void createAndShowGUI() {
JFrame frame = new JFrame("Geometry Calculator");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GeometryCalculator demo = new GeometryCalculator();
demo.addComponentToPane(frame.getContentPane());
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
try {
UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
} catch (UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
} catch (IllegalAccessException ex) {
ex.printStackTrace();
} catch (InstantiationException ex) {
ex.printStackTrace();
} catch (ClassNotFoundException ex) {
ex.printStackTrace();
}
UIManager.put("swing.boldMetal", Boolean.FALSE);
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
問題在哪裏？ –
@Sergiy我很抱歉不清楚。 Eclipse給我這個錯誤信息：線程「AWT-EventQueue-0」中的異常java.lang.Error：未解決的編譯問題： \t CalcButtonListenerA無法解析爲類型 – kikiwelsh