您好,希望有人能告诉我我的关键事件做错了什么。
我正在使用卡片布局来浏览我的两个 JPanels atm。为此,我使用操作事件和关键事件。当按下按钮时, Action 事件将在 JPanel 之间切换,而当按下按键时,按键事件将隐藏按钮。按键事件一切都很好,它做了我想要的事情(在其中一个面板上调用一个方法来设置放置在其中的按钮的边界,例如:button.setBounds(-1, -1, 150, 40);但是当我按下任何按钮,按键事件都不会响应,尽管我按下的按钮上没有任何事件。下面是我的代码,为了简单起见,我删除了面板的不相关部分,就像它们应该做的那样。
预先感谢,如果我需要提供更多线索或更多编辑代码,请告诉我,我会尽力使代码更清晰。
public class PanelContainer extends JPanel implements ActionListener, KeyListener{
GamePanel game = new GamePanel();
MainMenuPanel mainMenu = new MainMenuPanel();
CardLayout cards = new CardLayout();
public PanelContainer(){
setLayout(cards);
this.setFocusable(true);
this.addKeyListener(this);
mainMenu.newGameButton.addActionListener(this);
add(mainMenu, "Card1");
add(game, "Card2");
}
@Override
public void actionPerformed(ActionEvent aevt){
cards.show(this, "Card2");
game.action();
}
@Override
public void keyTyped(KeyEvent kevt){
}
@Override
public void keyPressed(KeyEvent kevt){
}
@Override
public void keyReleased(KeyEvent kevt){
if(kevt.getKeyCode() == KeyEvent.VK_ESCAPE || kevt.getKeyChar() == 'O' || kevt.getKeyChar() == 'o'){
game.shw(); //shw() is a method inside GamePanel that sets the bounds of the buttons
}
else if (kevt.getKeyChar() == 'h' || kevt.getKeyChar() == 'H'){game.hid();}
}
}
public class MainMenuPanel extends JPanel
{
private URL workingDir = this.getClass().getResource("imgresources/brick_wall.png") ;
private ImageIcon icon = new ImageIcon(workingDir) ;
private Image img = icon.getImage();
//create and initiate buttons;
JButton newGameButton = new JButton("New Game");
JButton highScoreButton = new JButton("High Scores");
JButton controlsButton = new JButton("Controls");
Point[] points = new Point[1000];
public MainMenuPanel(){
add(newGameButton);
add(highScoreButton);
add(controlsButton);
setPoints();
}
public void setButtonsBounds(){
newGameButton.setBounds(450, 200, 200, 40);
highScoreButton.setBounds(450, 250, 200, 40);
controlsButton.setBounds(450, 300, 200, 40);
}
@Override
public void paintComponent(Graphics g){
try{
super.paintComponent(g);
Graphics2D d2 = (Graphics2D) g;
d2.setColor(new Color(0, 0, 0));
d2.fillRect(0, 0, this.getWidth(), this.getHeight());
setButtonsBounds();
for(int i=0; i<275; i++){
d2.drawImage(img, points[i].x +200, points[i].y, this);
}
}catch(Exception e){}
}
}
public class GamePanel extends JPanel implements Runnable{
JButton button = new JButton("Main Menu");
JButton button2 = new JButton("Exit Game");
void shw(){
add(button);
add(button2);
button.setBounds(400, 200, 150, 20);
button2.setBounds(400, 240, 150, 20);
}
void hid(){
button.setBounds(1, 1, 150, 20);
button2.setBounds(1, 40, 150, 20);
}
}
最佳答案
这是一个焦点问题。使用按键绑定(bind)而不是 KeyListener,这样您就不必担心这个问题(还有其他好处 - 请查看 Key Bindings tutorial 了解详细信息)。
这是我的 SSCCE这证明了我在说什么。请注意,KeyListener 和键绑定(bind)都会起作用,直到您按下按钮,然后只有绑定(bind)才起作用:
import java.awt.event.*;
import javax.swing.*;
public class KeyBindingsEg {
private static void createAndShowGui() {
PanelContainer mainPanel = new PanelContainer();
JFrame frame = new JFrame("KeyBindingsEg");
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();
}
});
}
}
@SuppressWarnings("serial")
class PanelContainer extends JPanel {
public PanelContainer() {
this.setFocusable(true);
this.addKeyListener(new MyKeyListener());
JButton newGameButton = new JButton("New Game");
newGameButton.addActionListener(new MyActionListener());
add(newGameButton);
setKeyBindings();
}
private void setKeyBindings() {
Action hideAction = new BindingAction(BindingAction.HIDE);
Action showAction = new BindingAction(BindingAction.SHOW);
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inputMap = getInputMap(condition);
ActionMap actionMap = getActionMap();
actionMap.put(BindingAction.HIDE, hideAction);
inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_H, 0), BindingAction.HIDE);
inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_H, KeyEvent.SHIFT_DOWN_MASK),
BindingAction.HIDE);
int[] showKeys = { KeyEvent.VK_O, KeyEvent.VK_ESCAPE };
actionMap.put(BindingAction.SHOW, showAction);
for (int key : showKeys) {
inputMap.put(KeyStroke.getKeyStroke(key, 0), BindingAction.SHOW);
inputMap.put(KeyStroke.getKeyStroke(key, KeyEvent.SHIFT_DOWN_MASK),
BindingAction.SHOW);
}
}
private class MyActionListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent aevt) {
System.out.println("button pressed");
}
}
private class MyKeyListener extends KeyAdapter {
public void keyReleased(KeyEvent kevt) {
if (kevt.getKeyCode() == KeyEvent.VK_ESCAPE
|| kevt.getKeyChar() == 'O' || kevt.getKeyChar() == 'o') {
System.out.println("KeyListener: show");
} else if (kevt.getKeyChar() == 'h' || kevt.getKeyChar() == 'H') {
System.out.println("KeyListener: hide");
}
}
}
private class BindingAction extends AbstractAction {
public static final String HIDE = "Hide";
public static final String SHOW = "Show";
public BindingAction(String text) {
super(text);
putValue(ACTION_COMMAND_KEY, text);
}
@Override
public void actionPerformed(ActionEvent evt) {
String actionCommand = evt.getActionCommand();
if (actionCommand.equals(HIDE)) {
System.out.println("key bindings: hide");
} else if (actionCommand.equals(SHOW)) {
System.out.println("key bindings: show");
}
}
}
}
关于一旦按下按钮,Java 键事件就不会执行,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/9150034/