输入侦听器鼠标并同时按下键

Question

I have JFrame which contains JPanel. How to write listener to check when key(let it be SHIFT) is pressed and mouse enters to the JPanel area at the same time?

Answer 1

The MouseEvent provides information about the state of various elements, including some keys, via it's modifier properties, for example...

@Override
public void mouseEntered(MouseEvent e) {
    int modifiersEx = e.getModifiersEx();
    int onmask = MouseEvent.SHIFT_DOWN_MASK;
    if ((modifiersEx & onmask) == onmask) {
        // Shift key is down
    }
}

Will allow you to detect when the Shift key is pressed when the mouse enters a given component.

Take a look at...

• MouseEvent
• How to Write a Mouse Listener

...for more details