如何检查按下的键是否是 Java KeyListener 中的箭头键？
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How to check if the key pressed was an arrow key in Java KeyListener?
提问by Click Upvote
Can you help me refactor this code:
你能帮我重构这段代码吗：
public void keyPressed(KeyEvent e)
{
if (e.getKeyCode()==39)
{
//Right arrow key code
}
else if (e.getKeyCode()==37)
{
//Left arrow key code
}
repaint();
}
Please mention how to check for up/down arrow keys as well.Thanks!
请提及如何检查向上/向下箭头键。谢谢！
采纳答案by OscarRyz
public void keyPressed(KeyEvent e) {
int keyCode = e.getKeyCode();
switch( keyCode ) {
case KeyEvent.VK_UP:
// handle up
break;
case KeyEvent.VK_DOWN:
// handle down
break;
case KeyEvent.VK_LEFT:
// handle left
break;
case KeyEvent.VK_RIGHT :
// handle right
break;
}
}
回答by Pooria
If you mean that you wanna attach this to your panel (Window that you are working with).
如果您的意思是要将其附加到您的面板（您正在使用的窗口）。
then you have to create an inner class that extend from IKeyListener interface and then add that method in to the class.
那么你必须创建一个从 IKeyListener 接口扩展的内部类，然后将该方法添加到类中。
Then, attach that class to you panel by: this.addKeyListener(new subclass());
然后，通过以下方式将该类附加到您的面板： this.addKeyListener(new subclass());
回答by TofuBeer
You should be using things like: KeyEvent.VK_UP instead of the actual code.
你应该使用类似的东西： KeyEvent.VK_UP 而不是实际的代码。
How are you wanting to refactor it? What is the goal of the refactoring?
你想如何重构它？重构的目标是什么？
回答by banjollity
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_RIGHT ) {
//Right arrow key code
} else if (e.getKeyCode() == KeyEvent.VK_LEFT ) {
//Left arrow key code
} else if (e.getKeyCode() == KeyEvent.VK_UP ) {
//Up arrow key code
} else if (e.getKeyCode() == KeyEvent.VK_DOWN ) {
//Down arrow key code
}
repaint();
}
The KeyEvent codes are all a part of the API: http://docs.oracle.com/javase/7/docs/api/java/awt/event/KeyEvent.html
KeyEvent 代码都是 API 的一部分：http: //docs.oracle.com/javase/7/docs/api/java/awt/event/KeyEvent.html
回答by Jaime
Just to complete the answer (using the KeyEvent is the way to go) but up arrow is 38 and down arrow is 40 so:
只是为了完成答案（使用 KeyEvent 是要走的路）但是向上箭头是 38，向下箭头是 40 所以：
else if (e.getKeyCode()==38)
{
//Up arrow key code
}
else if (e.getKeyCode()==40)
{
//down arrow key code
}
