[英]Printing out text when space bar is pressed
这是我的主程序正在执行的示例。 我想在按下空格键时调用一个方法,但是我写的这个示例仅打印出文本并更改布尔值不起作用。 我不确定自己在做什么导致它无法正常工作。
import java.awt.FlowLayout;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class Test implements KeyListener {
static boolean spacedPressed = false;
static JTextField text = new JTextField();
public static void main(String s[]) {
JFrame frame = new JFrame("JFrame Test");
JPanel panel = new JPanel();
panel.setLayout(new FlowLayout());
JLabel label = new JLabel("Test Label");
JButton button = new JButton();
button.setText("Press me");
panel.add(label);
panel.add(button);
frame.add(panel);
frame.setSize(300, 300);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
if(button.getModel().isPressed()){
System.out.println("pressed");
panel.add(text);
System.out.println(spacedPressed);
}
}
@Override
public void keyPressed(KeyEvent e) {
if(e.getKeyCode() == KeyEvent.VK_SPACE){
System.out.println("Pressed");
spacedPressed = true;
text.setText("Press worked.");
} else {
System.out.println("not pressed");
text.setText("Press didn't work.");
spacedPressed = false;
}
}
@Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
}
您需要将keyListener添加到您的组件中,例如按钮:
button.addKeyListener(new KeyListener() {
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_SPACE) {
System.out.println("Pressed");
spacedPressed = true;
text.setText("Press worked.");
} else {
System.out.println("not pressed");
text.setText("Press didn't work.");
spacedPressed = false;
}
}
});
目前你正在编写的代码inside
一个KeyKistener,这是不绑定到任何组件
因此,这里是修改后的代码,它将打印键事件(我从面板上删除了按钮,因此它没有捕获空格键事件):
public class Test_1 implements KeyListener {
static boolean spacedPressed = false;
static JTextField text = new JTextField();
public static void main(String s[]) {
JFrame frame = new JFrame("JFrame Test");
JPanel panel = new JPanel();
panel.setLayout(new FlowLayout());
JLabel label = new JLabel("Test Label");
JButton button = new JButton();
button.setText("Press me");
frame.addKeyListener(new Test_1());
panel.add(label);
// panel.add(button);
frame.add(panel);
frame.setSize(300, 300);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
if (button.getModel().isPressed()) {
System.out.println("pressed");
panel.add(text);
System.out.println(spacedPressed);
}
}
@Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_SPACE) {
System.out.println("Pressed");
spacedPressed = true;
text.setText("Press worked.");
} else {
System.out.println("not pressed");
text.setText("Press didn't work.");
spacedPressed = false;
}
}
@Override
public void keyReleased(KeyEvent e) {
System.out.println("Released");
}
@Override
public void keyTyped(KeyEvent e) {
System.out.println("Typed");
}
}
并按JFrame上的空格键输出示例:
Pressed
Typed
Released
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.