Where does focus remain?
Is focus left on the window that previously held focus, or is focus in limbo, on no window?
I've noticed that when I eat a message, it appears as if nothing has focus.
I return MA_NOACTIVATEANDEAT
The focus can't be in limbo. Something always has to have the focus, so it will either be the window that previously held the focus, or the new window that is activated by the mouse event.
The documentation for CWnd::OnMouseActivate tells us what will happen, depending on the value that you return from the function:
MA_ACTIVATE Activate CWnd object
MA_NOACTIVATE Do not activate CWnd object
MA_ACTIVATEANDEAT Activate CWnd object and discard the mouse event
MA_NOACTIVATEANDEAT Do not activate CWnd object and discard the mouse event
Since you're returning MA_NOACTIVATEANDEAT, the previously focused object will retain the focus and the mouse event will be discarded.
Related
I'm trying to implement system-wide drag operation with middle mouse button. It should override middle mouse drag behavior in other programs. Currently, I am handling global mouse events with system-wide hooks.
Problem is - many programs still receive and handle same events like I did not intercept them.
Here's what I tried:
not call the next hook for mouse down event: I never receive mouse up, so I don't know where and when to stop dragging
not call the next hook for mouse move: cursor slows down tremendously
not call the next hook for mouse up: most windows in the system stop reacting to mouse events completely after my drag is finished
always call the next hook in the chain: if the control under mouse has scroll in it, most of the time it will be scrolling while my drag is in progress. Also UWP apps continue receiving mouse events during my drag, so if a link in MS Edge happens to be under cursor when it started, and mouse does not leave Edge boundary, Edge receives click event, and new tab is opened
What I need is: when user holds middle mouse and starts dragging, my drag handler should be called, and no other handlers, like file drag, scroll, etc should happen.
I ended up with somewhat hacky solution:
do not call the next hook for mouse down for middle button
record where it was pressed
when handling mouse up, if user did not drag - replay the whole mouse up + mouse down using SendInput from a separate thread (to avoid deadlock due to reentrancy)
in windows, how can make a 'child' window beyond the parent window, and the parent window always in active status (GetActiveWindow() return parent), just like the combobox dropdown window.
I think these are the main points when trying to do this:
The pop-up is a top-level window which has the same parent as the control. (i.e. The pop-up is not a child of the control. It's not a child-window at all; it's a top-level window, but one without a thick window border etc. so it doesn't look like a normal top-level window.) That's why it can extend outside of the control's boundaries.
When the pop-up is created it is shown using ShowWindow(hWndPopup, SW_SHOWNA) so that it does not take the input focus. This prevents the parent window from going inactive.
When the pop-up is created you capture the mouse using SetCapture. You then track where the mouse is and highlight items within the pop-up when the mouse overlaps them. When the mouse button is clicked you act on whatever is under the mouse (or cancel the pop-up if the mouse isn't over it at all). Remember to respond to WM_CAPTURECHANGED, in case something else captures the mouse. And remember to ReleaseCapture when you are done.
The popup should handle WM_MOUSEACTIVATE by returning MA_NOACTIVATEANDEAT.
I have a window that's a CHILD window of another window. For reasons beyond me, NC_HITTEST never gets called on it, no mouse events are called for it (but rather reach its parent window).
Why is that? I want that child window to process his own mouse clicks.
NC_HITTEST is not likely a message you want to be catching for mouse events. You want to be catching WM_MOUSEMOVE, WM_LBUTTONDOWN, etc...
I have a little popup window used for selecting images sorted by groups, and I would like to add a selection box around whatever image is being hovered over. I am trying to this by overriding the mouseMoved event for the window but it seems that a window that has a border-less style mask receives no mouseMoved events even if you have set setAcceptsMouseMoved events to YES. Is there anyway to make a borderless window receive this events?
You need to allow the window to become the key window. By default, borderless windows cannot become key. Subclass NSWindow and override -canBecomeKeyWindow:
- (BOOL)canBecomeKeyWindow
{
return YES;
}
Aternatively, you can use an NSTrackingArea to do your mouse tracking, which may be easier/better anyway.
Usually, when a user holds the mouse pressed over a button, moves the mouse away from the window, and then releases it, the button can tell that the mouse has been released even though the release has actually occured outside the window.
When I inspect mouse clicks in my window, how can I imitate the same behavior?
When a mouse button being pushed down over the window I get the WM_XBUTTONDOWN message, but Windows don't treat it as if anything is logically being "clicked", so after the mouse leaves the window, no further messages will arrive at the window, which results in a "lost" WM_XBUTTONUP message.
When you receive the button down, you capture the mouse. That means that all the mouse events until releasing the capture will be reported to the window that captured the mouse.
See the documentation here. You also have a link to an example from that page.
Use the DragDetect() function.
https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-dragdetect?redirectedfrom=MSDN