是否可以在动作执行方法中有一个键事件，因为我正在使用gui的动作侦听器，但我想在某个按键上关闭我的应用程序
答案 0 :(得分：4)
您可以使用AbstractAction，就像类固醇上的ActionListener一样，然后通过按钮的setAction(...)方法将其分配给您的JButton，因为它是Action。然后我会使用Key Bindings，而不是KeyListener，因为这将允许我们轻松解决KeyListener组件焦点问题，并使用键绑定将完全相同的AbstractAction绑定到您的按键。
请注意，如果正确设置JButton或AbstractAction的助记符，则按下按钮时alt键组合将自动起作用。
下面这个可能会过度杀死你，但它允许在Key Bindings，JButton或JMenuItem中使用相同的动作，这有点棘手。
// 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();
}
}
}
这是我为another StackOverflow question创建的演示程序。这是完整的代码。它还演示了CardLayout的使用：
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类中添加此方法并在MainPanel的构造函数中调用它，则会将退出操作绑定到选择的击键：
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);
}
}