CODEWITHSUNDEEP
javaswingresizejframemouselistener
Waffle
Waffle

Reputation: 73

Real-time listening to JFrame height and width

I've got a situation where I would like to be able to know a JFrame's height and width as the user drags their mouse to resize the frame.

I researched this, and the answers provided at the following question helped me a tiny bit, but not all the way: Listen to JFrame resize events as the user drags their mouse?

My problem is: I have made my "HSFrame" class extend JFrame and implement ActionListener, MouseMotionListener (ActionListener is irrelevant to this question, however). What this question pertains to is MouseMotionListener.

I have a separate class called "CanvasPanel" that extends JPanel--this is where I use a graphics object to update real-time information by drawing strings.

public void mouseMoved(MouseEvent e)
{
}

public void mouseDragged(MouseEvent e)
{
    validate();
    canvas.repaint();
}

This is a code excerpt from my "HSFrame" class (extends JFrame, implements MouseMotionListener). In this code example, "canvas" is a CanvasPanel object, and I am calling its repaint() method whenever MouseDragged is called.

I chose to use a MouseMotionListener because this (supposedly) would give me real-time updates as opposed to ComponentListener's componentResized() method (which is tied to MouseReleased).

Everything updates 100% perfectly when I resize the frame from the top-left corner. The height, width, X, and Y values all repaint perfectly.

But it does not update in real-time when I resize from the bottom-right corner. And I don't know about you, but I prefer to resize things from the bottom-right.

In the "CanvasPanel" class itself, I extended ComponentListener and added a listener to an "HSFrame" object there--it does not update in real-time, which was fine, but it does repaint the height and width after the mouse is released, regardless of which corner the HSFrame was resized with.

Main question: Is it possible to get the MouseMostionListener to know that I am resizing the JFrame from the bottom-right? It hears when I move the frame around by clicking and dragging the title bar, and it hears when I resize from the top-left corner (which is also interacting with the title bar). It just doesn't hear when anything goes on to the other borders of the JFrame.

Upvotes: 4

Views: 1040

Answers (1)

eboix
eboix

Reputation: 5133

You don't have to do this with the mouse! Do it the easy way: Write a component listener. Have HSFrame implement ComponentListener and put your resize code in public void componentResized(ComponentEvent e).

I think that the mouseListener won't work because when you're dragging from the bottom right your mouse is not in the JFrame, so the event listener doesn't pick it up.

Upvotes: 3

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