I have an odd problem here.
I'm working on an application, and within one of my classes I'm monitoring my mouse events.
The weird thing is, my mouse move event will only get called if any mouse button is pressed.
I'm not even filtering for any button presses within the method; the method itself doesn't even get called unless I click on this object itself (the one that's monitoring it).
What generally causes this type of error to happen?
I'm not sure if it's relevant, but I have 2 different things monitoring my mouse inputs: 1) the main program monitoring the global mouse coordinates, and 2) an object within my program monitoring the mouse coordinates within itself.
Edit
So the problem has to be because mouse move event is generally used when people are dragging the cursor along the screen right?
My reason for not needing it like that is because I'm building a custom context menu of sorts, and I need to know when an item is hovered over.
It turns out that I didn't truly set everything within my class to enable mouse tracking.
I somehow thought if the class itself was set to have it enabled, I wouldn't need to set it to all the sub objects, but now I see how that wouldn't make any sense at all.
So just to clarify my solution:
The items that I needed to track my cursor's position needed to have
setMouseTracking(true);
Related
I have a strange issue that I have been unable to determine the cause. Basically, I created a 2D view with pan and zoom functionality and a scene with items that can moved with grid snapping. To move an item in the scene I extended Scene::mousePressEvent to get a pointer to the item and Scene::mouseMoveEvent to keep the item tracked on the cursor. To drop the item, I used Scene::mousePressEvent again. To pan, I extended View::mousePressEvent, View::mouseReleaseEvent, and View::mouseMoveEvent and to zoom I extended View::wheelEvent.
Now for the symptoms:
I start the application with an item in the Scene. If I click and hold, then move the mouse, the item moves as intended. As soon as I release the mouse button, the item stops moving. I can click to drop and the item is placed according to the drop code in Scene::mousePressEvent. Try again and still the item only moves when the mouse button is pressed.
Then comes the strange part: If I use the mouse wheel to zoom the View, everything performs as expected after that event. The mouse is clicked to select an item, it moves as I move the mouse and drops when I click again.
So the obvious solution:
wheelEvent(new QWheelEvent(QPointF(0,0),0,Qt::NoButton,Qt::NoModifier));
called at the creation of the View and everything works fine. It calls the extended View::wheelEvent with no change to the view and before the scene is even created, but afterwards the programs behaves as expected.
So I'm here to see if any of the excellent Qt experts out there can explain this strange behavior. Any comments or direction are appreciated.
In case it helps, here is the View::wheelEvent override code. tform is a QTransform with which I maintain zoom. Also, I've tried with and without the call to the base method but there is no change in behavior.
void SchematicView::wheelEvent(QWheelEvent* event)
{
// Scale the view / do the zoom
double scaleFactor = 1.1;
if(event->delta() > 0 && tform.m11() < max_zoom) {
tform.scale(scaleFactor,scaleFactor);
} else if (event->delta() < 0 && tform.m11() > min_zoom){
tform.scale(1.0/scaleFactor,1.0/scaleFactor);
}
setTransformationAnchor(QGraphicsView::AnchorUnderMouse);
setTransform(tform);
QGraphicsView::wheelEvent(event);
}
Without a SSCCE to look at and test with, it's hard to say for sure, but what you're describing sounds a lot like your mouseMoveEvent() callback is only getting called when the mouse button is being held down during the move. That, in turn, sounds a lot like the expected behavior for mouseMoveEvent(), as documented in QWidget::mouseMoveEvent():
If mouse tracking is switched off, mouse move events only occur if a
mouse button is pressed while the mouse is being moved. If mouse
tracking is switched on, mouse move events occur even if no mouse
button is pressed.
If that is indeed the problem, then a call to setMouseTracking(true) may get you the behavior you are looking for.
On a broader level, note that there are easier ways of obtaining the behavior you are trying to implement -- for example, to allow the user to drag and drop items in a QGraphicsScene, all you really have to do is call setFlags(QGraphicsItem::ItemIsMovable) on any QGraphicsItems that you want the user to be able to drag around. No hand-coding of event handlers is necessary unless you are trying to obtain some non-standard behaviors.
I need to know if there is a code in c++ that allows to simulate a click, on a background window (if that's impossible, a foreground window will do fine), without moving the mouse.
I also need to click on specific coordinates, and drag an item to some other position (always without moving the mouse).
Example:
my mouse pointer is at (500,700),
but i need to left click at (100,150),
and drag to (700,300).
I need to be able to move my mouse pointer without affecting the program,
and the program must run correctly without moving, or locking, the mouse pointer.
If this action is impossible in c++, a VB code will be apreciated.
From a C++ Windows application, you can call Windows API directly by first finding the window using FindWindow that will give you the window handle you want, then finding the area within this window that you want to click. You can use API like GetWindowRect for this.
Finally, you can send this window, or an area within it, mouse messages using mouse_event function to cause the mouse to move, click, drag and let go at a new location.
My application has a big graphics area with some controls (sliders, buttons, text edit controls) in a side panel. The graphics area understands some keyboard commands.
My problem is that when a control in the side panel is in focus, the main graphics area won't receive any keyboard commands, so this confuses the users. However, for some controls, this is intended, e.g. text edit controls.
What I want is the focus to automatically return to the graphics area at the earliest possible occasion (which I call "greedy" focus) -- e.g. when text editing is finished (Enter key), or when the user has selected an item from a combo box.
I am looking for a clean and robust strategy for dealing with the problem, either using Windows API or Borland Vcl.
I'd appreciate if you want to share your ideas.
I haven't fully solved the problem yet, but a very useful message to intercept on form level is CM_DIALOGKEY (Borland Vcl only). It gets sent for every key that is normally used for navigating within the UI. That is, cursor keys, tab and shift-tab, Enter and possibly others.
I've added an event handler for CM_DIALOGKEY that returns the focus to the graphics area and also forwards the key press to that component. This way the user can still control the UI elements via keyboard (important for text entry), but cursor keys are handled by the graphics area.
I know what you mean I had similar problem with some BIG apps lice CAD/CAM ...
My solution is simple, robust and I use it for years.
1.all keystrokes handling for that gfx area
must be done in events of the Form where the area is located
not in panels,paint box whatever...
2.create unfocus function (preferably member of form but it is not required)
this function will loose focus of any VCL item
so the focus goes to form itself which is what you want
I am using this:
//---------------------------------------------------------------------------
void main_unfocus()
{
Main->bt_unfocus->Visible=true;
Main->bt_unfocus->SetFocus();
Main->bt_unfocus->Visible=false;
}
//---------------------------------------------------------------------------
Main is the Form pointer
bt_unfocus is button (can be any focusable VCL component)
I place this button usually on the left upper corner of App and set its size to 2x2 pixels
it is invisible at start
the idea is to set focus to it (but first unhide it so no exception is thrown)
and then hide it so it loses focus
work well in BCB5 and BDS2006 (did not used it with any other IDE)
as you can see most of the time is this component invisible
4.now when to call main_unfocus ?
when you go with mouse from outside to inside of your gfx area (OnMouseMove event)
or when you click on it
also you can combine this with remembering if the focus is or not in gfx area
that can be done with events like OnExit ...
or when you hit Esc while focus is inside edit box ...\
I am sure you grasp the idea and adjust this to your needs
Hope it helps
I'm making my first game in Irrlicht (C++), an RTS with mouse control
and when you select a tile (by clicking on it) it lights up and some gui button appear on the screen (not in a gui window mind you, I like it this way):
http://i1139.photobucket.com/albums/n549/Adam_Halley-Prinable/Untitled2.png
However, since i switched to mouse control, the buttons wont register my mouse clicks. The click goes straight through the button and selects the tile behind instead:
http://i1139.photobucket.com/albums/n549/Adam_Halley-Prinable/Untitled3.png
Is there a way I can say "Buttons get top priority for clicks"?
I'm using MyEventReceiver, which i've messed around with to accept mouse clicks and that.
Thanks a bunch :D
If anyone else has the same problem, ill tell you how I solved it :)
Go through the MyEventReceiver.h and get rid of all the "return true;"'s in the mouse section.
Don't ask me why, but it works, and appears to have no side effects. Make sure you leave the "return false;" at the end of the section there.
Your event receiver fires before the GUI gets access to the event, if you want to pass it to the GUI then you can do this by manually posting it to the GUIEnvironment in your event receiver.
if (guienv->postEventFromUser(event))
return true; // abort because the gui wanted it
// .. pick nodes
// possibly post event to scene manager
return true; // remember to return true so gui/smgr don't get the event again
I am writing Qt application which plays a fade-in animation whenever the mouse is moved to a certain area in the screen, and a fade out animation whenever the mouse is moved out of that same area.
I've already found a similar question here in stack overflow, however, it does not quite answer my question. (similar question here)
If I install an event filter to the application, will I be able to see ALL the events in the application even if it's outside my widget window?
If not, I am aware of an alternative involving QWidget::grabMouse() inside a reimplementation of leaveEvent(). But if I do so, will I be able to interact with anything OUTSIDE my application?
edit: though i am using the Qt library, my application is only for deployment to Windows.
I'm fairly the certain the answer is no, because events outside of your widgets are handled by the OSs window manager (and propagated onto whatever application is in that space).
However you can get the mouse position anywhere on the screen by calling QCursor::pos(), you could poll at regular intervals to find out where the mouse is.
You could try creating a completely transparent window that stays on top of the area where you want to receive mouse events, with the Qt::WindowStaysOnTopHint, Qt::FramelessWindowHint and Qt::ToolTip flags (the last one might prevent the window from receiving the focus), the Qt::WA_TranslucentBackground attribute and the mouse tracking enabled.
If you are on Windows, you can create a global hook to receive every mouse message (right before it's sent to the window under the mouse pointer). Unfortunately I don't know whether this functionality exists in other OSs.