java - 为什么我的 ActionListener 不起作用？
问题描述
我正在创建一个简单的应用程序来编码文本，但我正在努力处理一些 ActionListeners。当我从 JComboBox 中选择某些东西时，必须发生一些事情（如果您选择 Caesar's Cipher，则必须出现偏移量，如果您选择 Beaufort，则偏移量将消失；偏移量是 JTextField）并根据选择执行按钮将得到相应的 ActionListener 实现。问题是，当我选择 Caesar's Cipher 时，没有任何反应，即使我添加了实现 ActionListener 的 CaesarsCipher 来编码文本，也不会起作用。
MyFrame.java
package cipher;
import java.awt.BorderLayout;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
@SuppressWarnings("serial")
class MyFrame extends JFrame {
private JButton executeButton;
private ComboBoxPanel leftPanel;
private TextPanel rightPanel;
public MyFrame(String title) {
super(title);
//Initiate the frame
initFrame();
//Initiate the button that need to be pressed to execute a cipher
initButton();
//Init the panels
initPanel();
//Pack everything together;
packing();
//Make the frame visible to the user
setVisible(true);
}
//////////PACKING EVERYTHING TOGETHER//////////
private void packing() {
add(executeButton,BorderLayout.SOUTH);
add(leftPanel, BorderLayout.WEST);
add(rightPanel, BorderLayout.EAST);
}
//////////INITIATING THE FRAME WITH ALL COMPONENTS//////////
private void initPanel() {
leftPanel = new ComboBoxPanel();
rightPanel = new TextPanel();
}
private void initButton() {
executeButton = new JButton("Execute cipher");
}
private void initFrame() {
setSize(800,400);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setLayout(new BorderLayout());
setResizable(false);
}
//////////HIDE THE OFFSET WHEN CHOOSING ALGORITHMS THAT DO NOT REQUIRE OFFSET//////////
public void hideOffset() {
leftPanel.hideOffset();
}
public void showOffset() {
leftPanel.showOffset();
}
//////////UPDATE LEFT PANEL AFTER HIDING OFFSET//////////
public void updateLeftPanel() {
leftPanel.updatePanel();
}
//////////LISTENERS//////////
/////COMBO BOX/////
public void addComboBoxListener(ActionListener comboBoxListener) {
leftPanel.addComboBoxListener(comboBoxListener);
}
/////EXECUTE BUTTON/////
public void addExecuteButtonListener(ActionListener executeButtonListener) {
executeButton.addActionListener(executeButtonListener);
}
//////////GETTERS//////////
/////OFFSET GETTER/////
public Integer getOffset() {
return Integer.parseInt(leftPanel.getOffset());
}
/////INPUT GETTER/////
public String getInputText() {
return rightPanel.getInputText();
}
//////////SETTERS//////////
/////OUTPUT TEXT SETTER/////
public void setOutputText(String text) {
rightPanel.setOutputText(text);
}
}
组合框面板.java
package cipher;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JComboBox;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.Border;
@SuppressWarnings("serial")
class ComboBoxPanel extends JPanel {
private final String []CIPHERS = {"Caesar's Cipher", "ROT13", "Beaufort Cipher", "Autokey Cipher"};
@SuppressWarnings("rawtypes")
private JComboBox comboCiphers;
private JTextField offset;
public ComboBoxPanel() {
initSize();
initComboBox();
initBorder();
initLayout();
initTextField();
packing();
}
private void initTextField() {
offset = new JTextField(10);
}
private void initLayout() {
setLayout(new GridBagLayout());
}
private void packing() {
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.ipadx = 10;
add(comboCiphers,gbc);
gbc.gridy = 1;
add(offset,gbc);
}
private void initBorder() {
Border outer = BorderFactory.createEmptyBorder(5, 5, 5, 5);
Border inner = BorderFactory.createTitledBorder("Choose the cipher");
setBorder(BorderFactory.createCompoundBorder(outer, inner));
}
@SuppressWarnings({ "unchecked", "rawtypes" })
private void initComboBox() {
comboCiphers = new JComboBox(CIPHERS);
}
//Remainder: delete this, let the layout to do its job.
private void initSize() {
Dimension size = getPreferredSize();
size.width = 390;
setPreferredSize(size);
}
public void hideOffset() {
offset.setVisible(false);
}
public void showOffset() {
offset.setVisible(true);
}
public void updatePanel() {
revalidate();
repaint();
}
public void addComboBoxListener(ActionListener comboBoxListener) {
comboCiphers.addActionListener(comboBoxListener);
}
public String getOffset() {
return offset.toString();
}
}
文本面板.java
package cipher;
import java.awt.Color;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.border.Border;
import javax.swing.border.LineBorder;
@SuppressWarnings("serial")
class TextPanel extends JPanel {
private JTextArea inputArea, outputArea;
private JScrollPane inputScroll, outputScroll;
public TextPanel() {
//////////PANEL METHODS///////
/*
//Initiate the size of the panel
initSize();
*/
//Initiate the border of the entire panel
initBorder();
//Setup the layout of the panel
initLayout();
//////////TEXT AREAS METHODS///////
//Initiate the text areas
initTextArea();
//Initiate the borders for the 2 text areas
initTextAreaBorder();
//Create scrolls for both text areas
initScrollPane();
//Pack everything together
packing();
}
private void packing() {
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.weightx = 1;
gbc.weighty = 1;
gbc.fill = GridBagConstraints.BOTH;
add(inputScroll,gbc);
gbc.gridx = 0;
gbc.gridy = 1;
gbc.weightx = 1;
gbc.weighty = 1;
add(outputScroll,gbc);
}
private void initScrollPane() {
inputScroll = new JScrollPane(inputArea);
outputScroll = new JScrollPane(outputArea);
}
private void initTextAreaBorder() {
inputArea.setBorder(new LineBorder(Color.black));
outputArea.setBorder(new LineBorder(Color.black));
}
private void initBorder() {
Border outer = BorderFactory.createEmptyBorder(5, 5, 5, 5);
Border inner = BorderFactory.createTitledBorder("Text");
setBorder(BorderFactory.createCompoundBorder(outer,inner));
}
private void initLayout() {
setLayout(new GridBagLayout());
}
private void initTextArea() {
inputArea = new JTextArea(10,77);
outputArea = new JTextArea(10,77);
outputArea.append("Output...");
outputArea.setEditable(false);
}
public void addComboBoxListener(ActionListener comboBoxListener) {
//.addActionListener(comboBoxListener);
}
/*private void initSize() {
//setPreferredSize sets the minimum
Dimension size = getPreferredSize();
size.width = 390;
setPreferredSize(size);
}*/
public String getInputText() {
return inputArea.toString();
}
public void setOutputText(String text) {
outputArea.append(text);
}
}
应用控制器.java
package cipher;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComboBox;
public class ApplicationController{
private MyFrame frame;
public ApplicationController(MyFrame frame) {
this.frame = frame;
this.frame.addComboBoxListener(new ComboBoxListener());
}
class ComboBoxListener implements ActionListener {
@SuppressWarnings("rawtypes")
@Override
public void actionPerformed(ActionEvent e) {
JComboBox c = (JComboBox) e.getSource();
String selected = c.getSelectedItem().toString();
if(selected.equalsIgnoreCase("Caesar's Cipher")) {
frame.addExecuteButtonListener(new CaesarsCipher());
frame.showOffset();
frame.updateLeftPanel();
} else if(selected.equalsIgnoreCase("ROT13")) {
frame.showOffset();
frame.updateLeftPanel();
} else if(selected.equalsIgnoreCase("Beaufort Cipher")) {
frame.hideOffset();
frame.updateLeftPanel();
} else if(selected.equalsIgnoreCase("Autokey Cipher")) {
frame.hideOffset();
frame.updateLeftPanel();
}
}
}
class CaesarsCipher implements ActionListener {
public void actionPerformed(ActionEvent e) {
int offset = frame.getOffset();
char []text = frame.getInputText().toCharArray();
for(int i = 0 ; i < text.length ; i++) {
text[i] = (char)(((int)text[i] + offset) % 26);
}
String newText = new String(text);
frame.setOutputText(newText);
}
}
}
请有人解释什么是错的。我准备从错误中吸取教训。谢谢。
解决方案
您没有创建 applicationController 的实例，因此从未创建过您的组合框侦听器。
将来，您不应该扩展 JFrame。您所需要的只是它的一个实例。您还通过添加这些额外的添加侦听器方法增加了复杂性。
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