KeyListener，keyPressed与keyTyped [英] KeyListener, keyPressed versus keyTyped

问题描述

我有一个JFrame（好吧，一个扩展JFrame的类），我想在按F5键时执行操作。所以，我让类实现了KeyListener。有了它，有三个方法，keyPressed，keyReleased和keyTyped。

I have a JFrame (well, a class which extends JFrame) and I want to do an action when I press the F5 key. So, I made the class implement KeyListener. And with that, came three methods, keyPressed, keyReleased, and keyTyped.

我应该使用哪些方法来监听F5被按下？ keyPressed或keyTyped？我目前有以下内容，但是当我按下F5时它不会打印任何内容。

Which of these methods should I use to listen for F5 being pressed? keyPressed or keyTyped? I currently have the following, however it does not print anything when I press F5.

public void keyPressed(KeyEvent e) {
    if(e.getKeyCode() == KeyEvent.VK_F5)
        System.out.println("F5 pressed");
}

public void keyReleased(KeyEvent arg0) {
    // TODO Auto-generated method stub

}

public void keyTyped(KeyEvent arg0) {
    // TODO Auto-generated method stub

}

推荐答案

keyPressed - when the key goes down
keyReleased - when the key comes up
keyTyped - when the unicode character represented by this key is sent by the keyboard to system input.

我个人会为此使用keyReleased。只有当他们举起手指时才会开火。

I personally would use keyReleased for this. It will fire only when they lift their finger up.

请注意，keyTyped仅适用于可以打印的东西（我不知道F5是否可以）如果关键被按下，我相信会一遍又一遍地开火。这对于诸如......在屏幕上移动角色等内容非常有用。

Note that keyTyped will only work for something that can be printed (I don't know if F5 can or not) and I believe will fire over and over again if the key is held down. This would be useful for something like... moving a character across the screen or something.

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