问题
I tried to make it so that,if I pressed the right/left key, the sprite/Mario would face right/left. If I pressed the right key, he would face right. But for some reason, When I pressed the left key, he won't face left.
Source Code: First ,Second
Images
回答1:
"To fire keyboard events, a component must have the keyboard focus."—How to Write a Key Listener
回答2:
Don't use a KeyListener. Instead use Key Bindings which are more flexible and are used by all Swing components.
来源：https://stackoverflow.com/questions/6728389/java-animation-with-key-listener