我可以在一个类中使用多个ActionListener吗？
考虑下面过于简化的例子; 其中一些用伪代码编写，以简洁起见。 当我尝试按原样运行时，我收到编译器错误，指出已在我的main方法中找到actionPerformed 。 但是，如果我重命名它，对actionPerformed2说，它不再被ActionListener识别。
我是否需要将foo和foo2方法的侦听器组合到一个ActionListener方法中？ 在具有多个按钮对象的单个类中使用多个侦听器时，如何正确区分侦听器？
我刚刚开始玩摆动组件，所以我怀疑我可能不会问正确的问题……但是我可以随时编辑。 🙂
public class foo { declare button1, button2, button3 and panel1 public foo() { show panel1 with button1 and button2; } public foo2() { show panel1 with button3; } public void actionPerformed(ActionEvent e) { Object source1 = e.getSource(); do some stuff when button1 is clicked } public void actionPerformed(ActionEvent f) { Object source2 = f.getSource(); do some other stuff when button2 is clicked } public static void main(String[] args) { foo myFoo = new foo(); } }
为此使用匿名内部类。
例如，您永远不会写但代表一点的代码：
import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.*; public class Foo extends JPanel { private JButton btnA = new JButton("Button A"); private JButton btnB = new JButton("Button B"); private JButton btnC = new JButton("Button C"); public Foo() { btnA.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent arg0) { System.out.println("button A Action"); } }); btnB.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent arg0) { System.out.println("button B Action"); } }); btnC.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent arg0) { System.out.println("button C Action"); } }); add(btnA); add(btnB); add(btnC); } private static void createAndShowGui() { Foo mainPanel = new Foo(); JFrame frame = new JFrame("Foo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.getContentPane().add(mainPanel); frame.pack(); frame.setLocationByPlatform(true); frame.setVisible(true); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGui(); } }); } }
我自己，我正在使用更多的AbstractActions和更少的ActionListeners，甚至开始使用Command Design Pattern与PropertyChangeListener一起使用它。
例如，我最新的GUI的“视图”部分如下所示：
import java.awt.BorderLayout; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.KeyEvent; import java.beans.PropertyChangeListener; import java.util.HashMap; import java.util.Map; import javax.swing.*; import javax.swing.event.SwingPropertyChangeSupport; @SuppressWarnings("serial") public class View { enum TextAreaDestination { EGD_IMPRESSION("EGD Impression"), EGD_RECOMMENDATIONS("EGD Recommendations"), COLON_IMPRESSION("Colon Impression"), COLON_RECOMMENDATIONS("Colon Recommendations"), ERROR_MESSAGES("Error Messages"); private String text; private TextAreaDestination(String text) { this.text = text; } public String getText() { return text; } @Override public String toString() { return text; } } public enum GuiButtonText { GET_ONE_PROC("Get One Proc", KeyEvent.VK_O), GET_TWO_PROCs("Get Two Procs", KeyEvent.VK_T), INTO_FLOW("Into Flow", KeyEvent.VK_F), CLEAR_ALL("Clear All", KeyEvent.VK_C), F_U_PROC_FLAG("F/U Proc Flag", KeyEvent.VK_U), SIGN_NEXT("Sign/Next", KeyEvent.VK_S), EXIT("Exit", KeyEvent.VK_X); private String text; private int mnemonic; private GuiButtonText(String text, int mnemonic) { this.text = text; this.mnemonic = mnemonic; } public String getText() { return text; } public int getMnemonic() { return mnemonic; } } public static final String BUTTON_PRESSED = "Button Pressed"; private static final int TA_ROWS = 4; private static final int TA_COLS = 50; private JPanel mainPanel = new JPanel(); private SwingPropertyChangeSupport spcSupport = new SwingPropertyChangeSupport( this); private Map impressionRecMap = new HashMap(); public View() { JPanel textAreasPanel = createTextAreasPanel(); JPanel buttonsPanel = createButtonsPanel(); mainPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5)); mainPanel.setLayout(new BorderLayout(5, 5)); mainPanel.add(textAreasPanel, BorderLayout.CENTER); mainPanel.add(buttonsPanel, BorderLayout.PAGE_END); } private JPanel createButtonsPanel() { JPanel buttonsPanel = new JPanel(new GridLayout(2, 0, 5, 5)); for (final GuiButtonText guiBtnText : GuiButtonText.values()) { AbstractAction btnAction = new AbstractAction(guiBtnText.getText()) { {putValue(MNEMONIC_KEY, guiBtnText.getMnemonic()); } @Override public void actionPerformed(ActionEvent e) { spcSupport.firePropertyChange(BUTTON_PRESSED, null, guiBtnText); } }; JButton button = new JButton(btnAction); buttonsPanel.add(button); } return buttonsPanel; } private JPanel createTextAreasPanel() { JPanel textAreasPanel = new JPanel(); textAreasPanel.setLayout(new BoxLayout(textAreasPanel, BoxLayout.PAGE_AXIS)); for (TextAreaDestination textDest : TextAreaDestination.values()) { JTextArea tArea = new JTextArea(TA_ROWS, TA_COLS); tArea.setName(textDest.getText()); tArea.setWrapStyleWord(true); tArea.setLineWrap(true); impressionRecMap.put(textDest, tArea); JScrollPane scrollPane = new JScrollPane(tArea); JPanel outerPanel = new JPanel(new BorderLayout()); outerPanel.setBorder(BorderFactory.createTitledBorder(textDest.getText())); outerPanel.add(scrollPane); textAreasPanel.add(outerPanel); } return textAreasPanel; } public String textAreasGetText(TextAreaDestination key) { JTextArea textArea = impressionRecMap.get(key); if (textArea != null) { return textArea.getText(); } else { return ""; // throw exception } } public void textAreasSetText(TextAreaDestination key, String text) { JTextArea textArea = impressionRecMap.get(key); if (textArea != null) { textArea.setText(text); } else { // throw exception? } } public void textAreaAppend(TextAreaDestination key, String text) { JTextArea textArea = impressionRecMap.get(key); textArea.append(text); } public void clearAllAreas() { for (TextAreaDestination taDest : TextAreaDestination.values()) { textAreasSetText(taDest, ""); } } public void addPropertyChangeListener(PropertyChangeListener listener) { spcSupport.addPropertyChangeListener(listener); } public void removePropertyChangeListener(PropertyChangeListener listener) { spcSupport.removePropertyChangeListener(listener); } public JPanel getMainPanel() { return mainPanel; } public static void main(String[] args) { Control.main(args); } }
并且“控制”部分的一部分看起来像这样：
import java.awt.Component; import java.awt.Window; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import java.io.IOException; import java.io.InputStream; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.concurrent.ExecutionException; import javax.swing.*; import procedure.findings4.View.TextAreaDestination; public class Control { public static final boolean DEBUG = false; public static final String CENTRICITY_WINDOW_NAME = "Centricity EMR"; private DriverModel driverModel = null; private View view; private Map runnableMap = new HashMap(); public Control() { runnableMap.put(View.GuiButtonText.GET_ONE_PROC, new GetOneProcRunnable()); runnableMap.put(View.GuiButtonText.GET_TWO_PROCs, new GetTwoProcsRunnable()); runnableMap.put(View.GuiButtonText.INTO_FLOW, new IntoFlowRunnable()); runnableMap.put(View.GuiButtonText.CLEAR_ALL, new ClearAllRunnable()); runnableMap.put(View.GuiButtonText.SIGN_NEXT, new SignNextRunnable()); runnableMap.put(View.GuiButtonText.EXIT, new ExitRunnable()); } public void setView(View view) { this.view = view; view.addPropertyChangeListener(new ViewChangeListener()); } //.... private class ViewChangeListener implements PropertyChangeListener { @Override public void propertyChange(PropertyChangeEvent pcEvt) { if (pcEvt.getPropertyName().equals(View.BUTTON_PRESSED)) { Runnable run = runnableMap.get(pcEvt.getNewValue()); if (run != null) { run.run(); } } } } //....
请注意，我并不认为自己是这方面的专家，但我只是尽力管理复杂性。 可能有更好的方法来抚育这只猫。