仅当鼠标悬停在元素上至少一段特定时间时，如何触发MouseMove事件？

Question

I want to display a JFrame when a user move the mouse pointer inside over a certain area of a JPanel with a little delay. I show the JFrame by attaching a MouseAdapter to the JPanel and overriding the MouseMove method.

addMouseListener(new MouseAdapter() {
  @Override
  public void mouseMoved(MouseEvent e) {
    Point p= e.getLocationOnScreen();
    //check if Point p is within the boundaries of a rectangle.          
    //show a JFrame
  }                
});

To obtain the delay I think that I should use something like a Thread by using sleep , with the condition that it must be interrupted if the mouse is moved out of the boundaries, but I'm not sure that this is the best approach. Currently, I only see on SO questions related to JavaScript. What's the best way to do it in Java?

Answer 1

You can use the mouseEntered and mouseExited events from the MouseAdapter class.

You can set a timer on the mouseEntered method and check if the time spent on the object is >= the designated time in the mouseExited method and if so perform the action.

For the scenario of mouse left at the same point, you can use the Timer with a delay of how many ever seconds you want and setup a handler at mouseExited to stop the timer if the pointer is exited before the designated time.

Answer 2

Maybe a good solution is by using java.util.Timer .

addMouseListener(new MouseAdapter() {
 private int delay = 1000;//1 second
 private Timer timer = null;
 private int startTime =0;

  @Override
  public void mouseMoved(MouseEvent e) {
    Point p= e.getLocationOnScreen();
    boolean pointInArea=false;
    //check if Point p is within the boundaries of a rectangle.          
    if(pointInArea){
        //A JFrame is queued to be shown
        if(System.currentTimeMillis()-startTime>delay){
          //A JFrame has been already shown, then show a new one
          startTime = System.currentTimeMillis();
          timer = new Timer();                    
          timer.schedule(new TimerTask(){
              @Override
              public void run() {
                //LAUNCH JFrame
              }

          }, delay);                     
        }
     }
     else (!pointInArea && timer != null){
        timer.cancel();
        timer = null;                        
     }
  }                
});