Re: JPopupMenu positioning

Sabine Dinis Blochberger schrieb:
JPopupMenu positioning

I have a button, which, when clicked, should show a popup menu alignd
with its lower right corner.

The issue is that the popup menu shows in a wrong place with the first
click on the button, and in the correct one on every subsequent click,
even when moving or resizing the window.

source to display the problem:
[...]
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
// show the popupmenu
jPopupMenu1.show(jButton1, jButton1.getWidth() -
jPopupMenu1.getWidth(), jButton1.getHeight());
}
[...]
I've reproduced your problem. In the debugger I saw:
When the method is called for the first time, jPopupMenu1.getWidth()
returns 0, because the popup (a package-private member variable in
JPopupMenu) is not yet realized.
When it is called the for second/third/... time, jPopupMenu1.getWidth()
returns 20, and all is fine.

Any way to make it behave the way I want to (show up in the correct
place on the first try)? I have tried
[...]
JPopupMenu.pack()
I tried that, too, and didn't succeed.
Looking into JPopupMenu's source code, you see that JPopupMenu.pack() is
essentially a no-op, when JPopupMenu's popup member is not yet realized.


I also tried to set the popup menus on screen location directly, but
never found out how to get the correct point. This might be a possible
solution, to call jPopupMenu1.setLocation().
I would take a pragmatic route, and decide to display the popup menu
*left*-aligned, instead of *right*-aligned to the button:
private void jButton1ActionPerformed(java.awt.event.ActionEvent
evt) {
// show the popupmenu
jPopupMenu1.show(jButton1, 0, jButton1.getHeight());
}
I know this is not quite what wanted, but at least it behaves consistently.

--
Thomas


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