主要聽衆和行動進行

Question

是否有可能，因爲我使用的GUI操作監聽器有一個執行的操作方法的一個關鍵事件，但我想結束我的應用程序上的某個鍵按下

Answer 1

你可以使用一個AbstractAction ，它類似於類固醇上的ActionListener，然後通過按鈕的setAction(...)方法將其分配給您的JButton，因爲它是Action。然後我會使用Key Bindings而不是KeyListener，因爲這可以讓我們輕鬆解決KeyListener組件焦點問題，並使用鍵綁定將相同的AbstractAction綁定到您的按鍵上。

請注意，如果您正確設置了JButton's或AbstractAction的助記符，那麼alt-key組合會自動按下按鈕。

下面的這個可能會被你殺死，但它允許在鍵綁定，JButton或JMenuItem中使用這個操作，這有點棘手。

// class of mine to allow disposing of a window 
// It's a little complex to allow it to work with either a JButton 
// or a JMenuItem 
@SuppressWarnings("serial") 
class ExitAction extends AbstractAction { 
    public ExitAction() { 
     super("Exit"); 
     putValue(MNEMONIC_KEY, KeyEvent.VK_X); 
    } 

    @Override 
    public void actionPerformed(ActionEvent e) { 
     // get the button that caused this action 
     Object source = e.getSource(); 
     Window topWindow = null; 
     if (source instanceof AbstractButton) { 
      AbstractButton exitButton = (AbstractButton) source; 

      // get the parent top level window 
      topWindow = SwingUtilities.getWindowAncestor(exitButton); 
      if (topWindow == null) { // if null, then likely in a JMenuItem 
       // so we have to get its jpopupmenu parent 
       Container parent = exitButton.getParent(); 
       if (parent instanceof JPopupMenu) { 
        JPopupMenu popupMenu = (JPopupMenu) parent; 

        // get the invoker for the pop up menu 
        Component invoker = popupMenu.getInvoker(); 
        if (invoker != null) { 
         // and get *its* top level window 
         topWindow = SwingUtilities.getWindowAncestor(invoker); 
        } 
       } 
      } 
     } else if (source instanceof Component) { 
      // if in key bindings 
      topWindow = SwingUtilities.getWindowAncestor((Component) source); 
     } 
     if (topWindow != null) { 
      // dispose of the top-level window 
      topWindow.dispose(); 
     } 
    } 
} 

這是我爲another StackOverflow question創建的演示程序。這是完整的代碼。它還演示了使用CardLayout的：

import java.awt.BorderLayout; 
import java.awt.CardLayout; 
import java.awt.Component; 
import java.awt.Container; 
import java.awt.Dimension; 
import java.awt.GridBagLayout; 
import java.awt.GridLayout; 
import java.awt.Window; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.awt.event.KeyEvent; 

import javax.swing.AbstractAction; 
import javax.swing.AbstractButton; 
import javax.swing.Action; 
import javax.swing.ActionMap; 
import javax.swing.BorderFactory; 
import javax.swing.InputMap; 
import javax.swing.JButton; 
import javax.swing.JComboBox; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.JPopupMenu; 
import javax.swing.JTextField; 
import javax.swing.KeyStroke; 
import javax.swing.SwingUtilities; 

/** 
* https://stackoverflow.com/questions/30288947 
* /accessing-jcombobox-data-from-separate-jform 
* 
* @author Pete 
* 
*/ 
public class SimpleMultPanels { 
    private static void createAndShowGui() { 
     // create JFrame 
     JFrame frame = new JFrame("SimpleMultPanels"); 
     frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); 

     // add our MainPanel to the JFrame 
     frame.getContentPane().add(new MainPanel()); 
     frame.pack(); // pack it 
     frame.setLocationByPlatform(true); 
     frame.setVisible(true); // show it 
    } 

    public static void main(String[] args) { 
     // this is for starting our Swing app on the event thread 
     SwingUtilities.invokeLater(new Runnable() { 
      public void run() { 
       createAndShowGui(); 
      } 
     }); 
    } 
} 

@SuppressWarnings("serial") 
class MainPanel extends JPanel { 
    private static final KeyStroke EXIT_KEY_STROKE = KeyStroke.getKeyStroke(
      KeyEvent.VK_Z, KeyEvent.CTRL_DOWN_MASK);; 

    private CardLayout cardLayout = new CardLayout(); 

    // the three "card" JPanels that this JPanel displays: 
    private MenuPanel menuPanel = new MenuPanel(); 
    private HoldsComboBoxPanel holdsComboBoxPanel = new HoldsComboBoxPanel(); 
    private ShowSelectionPanel showSelectionPanel = new ShowSelectionPanel(); 

    // Actions for our JButtons 
    private ExitAction exitAction = new ExitAction(); 
    private ShowAction backToMenuAction = new ShowAction(this, "Back to Menu", 
      MenuPanel.NAME, KeyEvent.VK_B); 
    private ShowAction toHoldsComboAction = new ShowAction(this, "Combo Panel", 
      HoldsComboBoxPanel.NAME, KeyEvent.VK_C); 
    private ShowAction toShowSelectionAction = new ShowAction(this, 
      "Show Selection", ShowSelectionPanel.NAME, KeyEvent.VK_S); 

    public MainPanel() { 
     // add an ActionListener to the JComboBox 
     holdsComboBoxPanel.addComboBoxListener(new ActionListener() { 

      @Override 
      public void actionPerformed(ActionEvent e) { 
       // get the combo's selected String 
       String selection = holdsComboBoxPanel.getComboSelection(); 
       if (selection != null) { 
        // push it into showSelection 
        showSelectionPanel.setDisplayText(selection); 
       } 
      } 
     }); 

     // add Actions to class to allow swapping of cards and 
     holdsComboBoxPanel.addButtonAction(backToMenuAction); 
     holdsComboBoxPanel.addButtonAction(toShowSelectionAction); 
     holdsComboBoxPanel.addButtonAction(exitAction); // and to exit gui 

     showSelectionPanel.addButtonAction(backToMenuAction); 
     showSelectionPanel.addButtonAction(toHoldsComboAction); 
     showSelectionPanel.addButtonAction(exitAction); 

     menuPanel.addButtonAction(toHoldsComboAction); 
     menuPanel.addButtonAction(toShowSelectionAction); 
     menuPanel.addButtonAction(exitAction); 

     setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5)); 

     // set our layout 
     setLayout(cardLayout); 

     // and add our "card" JPanels 
     add(menuPanel, MenuPanel.NAME); 
     add(holdsComboBoxPanel, HoldsComboBoxPanel.NAME); 
     add(showSelectionPanel, ShowSelectionPanel.NAME); 

     setExitOnKeyStroke(EXIT_KEY_STROKE); // added 9/27/15 
    } 

    private void setExitOnKeyStroke(KeyStroke keyStroke) { 
     // do your key bindings 

     // first get ActionMap and InputMap 
     InputMap inputMap = getInputMap(WHEN_IN_FOCUSED_WINDOW); 
     ActionMap actionMap = getActionMap(); 

     // then the keystroke 
     String key = keyStroke.toString(); 

     inputMap.put(keyStroke, key); // map the keystroke to a String key 
     actionMap.put(key, exitAction); // map the same String key to the Action 
    } 

    // method that allows outside classes to swap views 
    public void showCard(String key) { 
     cardLayout.show(this, key); 
    } 
} 

@SuppressWarnings("serial") 
class HoldsComboBoxPanel extends JPanel { 
    // constant String that will be used by the CardLayout 
    public static final String NAME = "holds combobox panel"; 

    // sample data 
    private static final String[] DATA = { "Monday", "Tuesday", "Wednesday", 
      "Thursday", "Friday" }; 
    private JComboBox<String> comboBox = new JComboBox<>(DATA); 

    // JPanel to hold buttons to allow moving between cards 
    private JPanel buttonPanel = new JPanel(new GridLayout(1, 0, 5, 0)); 

    public HoldsComboBoxPanel() { 
     comboBox.setSelectedIndex(-1); 
     JPanel centerPanel = new JPanel(); 
     centerPanel.add(comboBox); 

     setLayout(new BorderLayout()); 
     add(centerPanel, BorderLayout.CENTER); 
     add(buttonPanel, BorderLayout.SOUTH); 
    } 

    // method to add a listener 
    public void addComboBoxListener(ActionListener listener) { 
     comboBox.addActionListener(listener); 
    } 

    // getter method 
    public String getComboSelection() { 
     return (String) comboBox.getSelectedItem(); 
    } 

    // create a new JButton with an Action and add to buttonPanel 
    public void addButtonAction(Action action) { 
     buttonPanel.add(new JButton(action)); 
    } 
} 

@SuppressWarnings("serial") 
class ShowSelectionPanel extends JPanel { 
    public static final String NAME = "show selection panel"; 
    private static final int PREF_W = 300; 
    private static final int PREF_H = PREF_W; 
    private JTextField displayField = new JTextField(10); 
    private JPanel buttonPanel = new JPanel(new GridLayout(1, 0, 5, 0)); 

    public ShowSelectionPanel() { 
     displayField.setFocusable(false); 

     JPanel centerPanel = new JPanel(); 
     centerPanel.add(displayField); 

     setLayout(new BorderLayout()); 
     add(centerPanel, BorderLayout.CENTER); 
     add(buttonPanel, BorderLayout.SOUTH); 
    } 

    // code to make our GUI a little larger 
    @Override 
    public Dimension getPreferredSize() { 
     Dimension superSz = super.getPreferredSize(); 
     if (isPreferredSizeSet()) { 
      return superSz; 
     } 
     int prefW = Math.max(superSz.width, PREF_W); 
     int prefH = Math.max(superSz.height, PREF_H); 
     return new Dimension(prefW, prefH); 
    } 

    // setter method 
    public void setDisplayText(String text) { 
     displayField.setText(text); 
     // or do whatever else you want to do with the selection 
    } 

    public void addButtonAction(Action action) { 
     buttonPanel.add(new JButton(action)); 
    } 

} 

@SuppressWarnings("serial") 
class MenuPanel extends JPanel { 
    public static final String NAME = "menu panel"; 
    private JPanel buttonPanel = new JPanel(new GridLayout(0, 1, 0, 5)); 

    public MenuPanel() { 
     setLayout(new GridBagLayout()); 
     add(buttonPanel); 
    } 

    public void addButtonAction(Action action) { 
     buttonPanel.add(new JButton(action)); 
    } 
} 

@SuppressWarnings("serial") 
class ShowAction extends AbstractAction { 
    private MainPanel mainPanel; 
    private String key; 

    /** 
    * Abstract Action used by JButtons 
    * 
    * @param mainPanel 
    *   : the JPanel that uses the CardLayout 
    * @param name 
    *   : The name displayed by the button 
    * @param key 
    *   : The key used in the CardLayout#show(String key) mehtod 
    * @param mnemonic 
    *   : the JButton's mnemonic char 
    */ 
    public ShowAction(MainPanel mainPanel, String name, String key, int mnemonic) { 
     super(name); 
     putValue(MNEMONIC_KEY, mnemonic); 
     this.mainPanel = mainPanel; 
     this.key = key; 
    } 

    @Override 
    public void actionPerformed(ActionEvent e) { 
     // tell the mainPanel to show the card associated with the key 
     mainPanel.showCard(key); 
    } 
} 

// class of mine to allow disposing of a window 
// It's a little complex to allow it to work with either a JButton 
// or a JMenuItem 
@SuppressWarnings("serial") 
class ExitAction extends AbstractAction { 
    public ExitAction() { 
     super("Exit"); 
     putValue(MNEMONIC_KEY, KeyEvent.VK_X); 
    } 

    @Override 
    public void actionPerformed(ActionEvent e) { 
     // get the button that caused this action 
     Object source = e.getSource(); 
     Window topWindow = null; 
     if (source instanceof AbstractButton) { 
      AbstractButton exitButton = (AbstractButton) source; 

      // get the parent top level window 
      topWindow = SwingUtilities.getWindowAncestor(exitButton); 
      if (topWindow == null) { // if null, then likely in a JMenuItem 
       // so we have to get its jpopupmenu parent 
       Container parent = exitButton.getParent(); 
       if (parent instanceof JPopupMenu) { 
        JPopupMenu popupMenu = (JPopupMenu) parent; 

        // get the invoker for the pop up menu 
        Component invoker = popupMenu.getInvoker(); 
        if (invoker != null) { 
         // and get *its* top level window 
         topWindow = SwingUtilities.getWindowAncestor(invoker); 
        } 
       } 
      } 
     } else if (source instanceof Component) { 
      // if in key bindings 
      topWindow = SwingUtilities.getWindowAncestor((Component) source); 
     } 
     if (topWindow != null) { 
      // dispose of the top-level window 
      topWindow.dispose(); 
     } 
    } 
} 

如果在mainPanel中類中添加這個方法，並調用它的mainPanel的構造函數，你會退出動作綁定到選擇的按鍵：

private void setExitOnKeyStroke(KeyStroke keyStroke) { 
     // do your key bindings 

     // first get ActionMap and InputMap 
     InputMap inputMap = getInputMap(WHEN_IN_FOCUSED_WINDOW); 
     ActionMap actionMap = getActionMap(); 

     // then the keystroke 
     String key = keyStroke.toString(); 

     inputMap.put(keyStroke, key); // map the keystroke to a String key 
     actionMap.put(key, exitAction); // map the same String key to the Action 
    } 

    // method that allows outside classes to swap views 
    public void showCard(String key) { 
     cardLayout.show(this, key); 
    } 
}