KeyTypedEvent KeyEvent的KeyCode始终为0吗? [英] KeyTypedEvent KeyEvent's KeyCode is always 0?

问题描述

我在NetBeans IDE中有一个Java Swing应用程序.

I have a Java Swing application in the NetBeans IDE.

我制作了一个表单，并将KeyListener附加到我的各种控件上，例如:

I made a form and attached a KeyListener to my various controls as such:

    jButton1.addKeyListener(new java.awt.event.KeyAdapter() {
        public void keyTyped(java.awt.event.KeyEvent evt) {
            keyTypedEvent(evt);
        }
    });

和 keyTypedEvent 的定义如下:

private void keyTypedEvent(java.awt.event.KeyEvent evt) 
{                               
System.out.println(evt);
appendDisplay(String.valueOf(evt.getKeyChar()));
} 

我在 evt 中添加了一个 println ，以查看会发生什么并验证我的键侦听器确实起作用.在构建和运行应用程序时，我意识到输出似乎总是有一个 keycode = 0

I added a println to the evt to see what happens and to verify that my keylistener does work. When I build and run my application, I realized that the output always seems to have a keycode = 0

为验证这一点，我将我的println更改为 evt.getKeyCode()，它始终返回0.

To verify this, I had changed my println to be evt.getKeyCode() and it is always returning 0.

我可能完全误解了KeyCode的功能，但是我认为它会与Oracle文档中的值相对应:

I could be completely misinterpreting what KeyCode does, but I thought that it would coorespond with the values in Oracle's documentation here:

http://docs.oracle.com/javase/7/docs/api/constant-values.html#java.awt.event.KeyEvent.VK_ESCAPE

例如，VK_ESCAPE的值为27.

For instance, VK_ESCAPE has a value of 27.

推荐答案

keyTyped()事件仅用于产生字符输入的键.如果您想知道何时按下或释放任何键，则需要实现 keyPressed()或 keyReleased().

The keyTyped() event is only used for keys that produce character input. If you want to know when any key is pressed or released, you need to implement keyPressed() or keyReleased().

通过 KeyEvent API:

键类型"事件是较高级别的事件，通常不依赖于平台或键盘布局.它们是在Unicode时生成的输入了字符，这是查找有关字符的首选方法字符输入....

"Key typed" events are higher-level and generally do not depend on the platform or keyboard layout. They are generated when a Unicode character is entered, and are the preferred way to find out about character input....

对于按键按下和键释放事件，getKeyCode方法返回事件的keyCode.对于键类型的事件，使用getKeyCode方法总是返回VK_UNDEFINED.

For key pressed and key released events, the getKeyCode method returns the event's keyCode. For key typed events, the getKeyCode method always returns VK_UNDEFINED.

这篇关于KeyTypedEvent KeyEvent的KeyCode始终为0吗?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！