qApp->setOverrideCursor() method works successfully, if I want to hide mouse cursor, except one condition. If I add a dialog that is modal, and while it is shown, if the cursor is out of dialog's borders, it is shown again. Have you got any idea about the problem?
It does not matter how the solution for hiding mouse cursor is; whether by Qt or at the operating system level. My operating system is Windows 7.
You cannot hide the mouse cursor when it leaves your window (or dialog-window), because it is then handled by the window-manager of your OS. A workaround would be to constrain the mouse to your window/dialog, so it cannot leave. You will either need to look through the MSDN to find the specific windows functions to do it, or do it like in kshegunov's code example on the Qt-forums: https://forum.qt.io/topic/61832/restrict-mouse-cursor-movement/12
Related
I have a C++ Qt 4 application written for Raspberry Pi. I'm experiencing an odd side-effect of showing a QMessageBox and I don't know enough about Qt to debug it.
The pi has a touchscreen, so I launch the application with unclutter to hide the mouse cursor. (Though this doesn't affect my issue... I have tried without unclutter just in case.)
I have sub-classed QLineEdit to override focusInEvent() and focusOutEvent() to select-all when a LineEdit gets focus, and deselect-all when it loses focus.
Before showing any QMessageBoxes, everything works perfectly - tapping on a QLineEdit selects all the text; tapping the next one de-selects the previous QLineEdit, and selects the new QLineEdit.
After showing a QMessageBox, my overridden events stop working, and QLineEdits no longer auto-select and de-select.
If I add:
msgBox.setWindowFlags(msgBox.windowFlags() | Qt::Popup);
before I exec() the QMessageBox, then text highlighting continues working normally, but the cursor is displayed and flickers while the QMessageBox is on the screen.
It seems like there is a side-effect of showing the QMessageBox that affects the calling window and my sub-classed QLineEdit boxes... but not if the QMessageBox has the Popup flag set!
I've tried storing and manually re-loading the flags on the main window, and that does nothing, so it doesn't appear to be flags on the main window.
One more oddity: everything works fine if I run the application remotely over XMing and SSH... it's only when it's run locally on the Pi in plain-old X11 that it freaks out.
Any thoughts on how to debug this? Thank you!
I was able to work around this by doing two things.
First, I updated the flags of the QMessageBox before opening it:
msgBox.setWindowFlags(Qt::Popup);
msgBox.exec();
and second, I hid the cursor in Qt code, rather than relying on Unclutter; this fixed the flickering cursor issue:
QApplication::setOverrideCursor(Qt::BlankCursor);
Background
I'm building an application which runs in the background, and where the mouse cursor is moved programmatically into a dialog when the dialog "pops up". I have done this using QCursor.setPos
Problem
The problem I'm having is that if the mouse button is pressed down when the user is interacting with something outside the application this might lead to unwanted things happening. For example if the user is changing the volume and the mouse is moved the volume might go to max or min
Question
Is there any way (in Qt) to do a mouseup programmatically?
If I do this before changing the position of the cursor it seems to me that there is less risk of problems (though there might be other problems resulting from this approach)
I am developing a touch application for Windows 7 with Qt/QML. The end-user-device has Windows 7's native touch behavior, i.e.: When touching the screen, a point appears on the last-touched-point, and when ending the physical touch, Windows puts that point on the now-touched point and runs in the on-clicked-Event.
Compared to the behavior one knows from standard Windows mouse-usage, this leads to a different behavior as soon as it comes to e.g. clicking some button: A mouse user will expect that the button changes color to the pressed-down-color when mouse button goes down, while the color changes to the default color again when the mouse button goes up.
In my application, I want to have a customized way of touch feedback: What is currently being touched should be marked using changed colors of buttons, imitating a "mouse goes down" when the actual physical touch begins and imitating a "mouse goes up" when the actual physical touch ends.
My application will run fullscreen, so an actual possibility would be to change the system's behavior on application start and change it back to default on applications end.
Such a behavior would effectively be the same as the standard behavior on e.g. all Android devices I know.
I searched through all the MouseArea and MultiPointTouchArea elements, trying to find a way to just make the click-reaction behavior different to the standard behavior. However I did not even find a way to capture the begin of the actual touch ... All the things which I want to happen at the begin of the touch actually happen when the touching ends.
Edit:
It does not matter if I use a QML button or a mousearea plus the MouseArea.pressed property: Nothing will be "pressed" before the finger leaves the touch and the onClicked() even is called.
Possibly related:
Adobe AIR: touch screen doesn't trigger mouse down event correctly - but I did not find a way to access the functions like Multitouch.inputMode (which are mentioned in the first reply) from a native Qt application.
How can I achieve the described behavior for my application?
The solution for this issue is to disable "Press and Hold" for the application. This is what can be done in a system-wide setting using ...
Control Panel -> Pen and Touch -> Touch -> Press and Hold -> Settings -> uncheck 'Enable press and hold for right-clicking'
The only solution I found to to this in native code can be found here:
http://msdn.microsoft.com/en-us/library/ms812373.aspx
I checked that this is at least still working for Windows 7. To get it working for QML, I searched for the QWindow* in QQmlApplicationEngine::rootObjects() and used its winId as a HWND. With that HWND, I called the TogglePressAndHold function from the link before app.exec().
I want to hide system cursor for 10s for some reason ,but I found
cursor.setShape(Qt.BlankCursor)
can only hide mouse cursor that is associated with QWidgets ,not in system wide ,i.e. when mouse cursor is hovering on QWidgets, it is invisible ,otherwise it is visible ,so is there any way to hide system cursor in system wide?
The win32 system call ShowCursor works per-window only. You can access this from either ctypes or pywin32's win32api. But apparently the cursor drawing is controlled by display driver and can only be affected by specific windows. You can't force another window to hide its cursor. Two options:
use ShowCursor(False) on your window, and for the display background, create a root window application that you spawn from your GUI app, it hides cursor; your app would cause it to exit after 10 seconds, but again if user moves mouse over other app windows they will see cursor.
make your application a root window application; then while in view, ShowCursor(False) will make cursor disappear everywhere on screen except system toolbar (which is a good thing).
I don't think it is a good idea anyways; what if your app crashes while the mouse is hidden? Then user can't use their desktop easily. Definitely good reason that this is not allowed.
Best approach is to think of a different solution to whatever problem led you to try cursor hiding.
From what I see, QApplication::mouseButtons() may return no buttons even when a button is held down. This happens when you have clicked a side of a window for re-sizing. It's coherent with the docs because mouseButtons() reflects the state from the flow of QEvent::mouseButtonPress, etc. However, I need just to know if the button is held down. Does any one know if it's possible through the Qt API?
I think it's not possible. Mouse events outside an application's window are not passed to its event handlers. Dragging mouse borders is one of such events, it's processed by the window system. Another example is clicking on other windows. Usually an application doesn't know what the user does with other windows. You need to install system-wide event listener or use native API features(e.g. GetAsyncKeyState on Windows) to determine that. This behavior is unusual and possibly dangerous. In most cases it's not useful, and it seems that Qt doesn't have this ability.