contextMenuEvent

[mickey]

Hi, I implemeted this below to have a mouse menu; problem: when I click and move mouse and then release, menu appear; If I click and move I traslate the scene; and when I release mouse, i don't want menu mouse appear; how this? (is there a QT way?) thanks

void MyWidget::contextMenuEvent(QContextMenuEvent* event)

void MyWidget::contextMenuEvent(QContextMenuEvent* event)

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[mickey]

Anyone know this?

[wysota]

Could you explain what the exact problem is? What you expect and what you get?

[mickey]

The problem is this: if I click right mouse contextMenuEvent is called and a popupmousemenu is drawn; problem is if I press mouse dx and move mouse my scene will be rotate; after this, when I release mouse, contextMenuEvent is called: and this isn't right; mouse menu have to be drawn only if I click (in a point) and release immediately (without move).are u understand?

[jpn]

Catch mouse button press/release events, compare press/release offset, show the context menu only if the offset was in allowed range.

[wysota]

As far as I know the context menu on Windows is shown upon release of the button (at least in Qt4). Do you receive the event after pressing the button?

How does your menu event handler look like?

[jpn]

wysota, yep, release event comes before the context menu event. As far as I understood correctly, he wants to avoid showing of context menu if mouse was moved during press and release.

mickey, the context menu event is sent regardless of that if the mouse was moved or not. You will have to examine the possible movement manually.

[wysota]

I think you should just ignore the event based on the geometry, content or simply previous mouse events.

[mickey]

event is called when I release mouse! But If I pressed dx button for do traslation, menu mustn't appear!

[jpn]

event is called when I release mouse! But If I pressed dx button for do traslation, menu mustn't appear!

Yes, we understood the problem. Here's a couple of pseudo algorithms to solve it. The choice is yours:

mousePressEvent:
    pressPoint = mouse press event's position
 
contextMenuEvent:
    if distance between context menu event's position and pressPoint is less than something
        show context menu
    else do nothing

mousePressEvent:
    pressPoint = mouse press event's position

contextMenuEvent:
    if distance between context menu event's position and pressPoint is less than something
        show context menu
    else do nothing

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or

mousePressEvent:
    pressPoint = mouse press event's position
 
mouseReleaseEvent:
    if distance between mouse release event's position and pressPoint is less than something
        showContextMenu = true
    else
        showContextMenu = false
 
contextMenuEvent:
    if showContextMenu
        show context menu
    else do nothing

mousePressEvent:
    pressPoint = mouse press event's position

mouseReleaseEvent:
    if distance between mouse release event's position and pressPoint is less than something
        showContextMenu = true
    else
        showContextMenu = false

contextMenuEvent:
    if showContextMenu
        show context menu
    else do nothing

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or

mousePressEvent:
    showContextMenu = true
 
mouseMoveEvent:
    showContextMenu = false
 
contextMenuEvent:
    if showContextMenu
        show context menu
    else do nothing

mousePressEvent:
    showContextMenu = true

mouseMoveEvent:
    showContextMenu = false

contextMenuEvent:
    if showContextMenu
        show context menu
    else do nothing

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or ....

[wysota]

Hmm... could you provide a minimal compilable example which reproduces the problem? Because as for now we're talking about a bit abstract behaviour.

[mickey]

i think so long...but Do I have use some flag to do this?when right mouse button do some things (translate, change color of scene where I pick (only if I have a pushbutton down). so if traslate or changing color (it works), when I releae mouse appear menu; I can follow advice of jpn (for every things I set a flags menuContext=false), but I hoped find a Qt way....such as ignore() (but I haven't idea how use it):..

[wysota]

If you do, remember to reimplement also the release event to clear values which were set in previous handlers.

[mickey]

I'm trying this; with mouseMoving flag it works; but I wonder how use ignore() function

void MyWidget::contextMenuEvent(QContextMenuEvent* e) {
	if (mouseMoving) {mouseMoving = false; return;}
         //if (mouseMoving)     e->ignore(); //Must I use ignore() in that way?

void MyWidget::contextMenuEvent(QContextMenuEvent* e) {
	if (mouseMoving) {mouseMoving = false; return;}
         //if (mouseMoving)     e->ignore(); //Must I use ignore() in that way?

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Where do I have to use ignore? and how cal it? thanks