How to minimize window when the taskbar icon is clicked? - qt

I have a Qt application with borderless window. So, I am creating my application window with CreateWindow() and then I have QWidget which uses the HWND.
Everything works fine, except that when the application is maximized and the Windows taskbar is set to auto-hide. In that case, if I click on the application icon, the program is not minimized. Even stranger is the fact that this only happens if the application is on my primary monitor. If it's on another monitor, everything works fine. Or, if the taskbar is not set to auto-hide, everything works fine on any monitor.
When the taskbar is set to auto-hide, on my primary screen the taskbar wasn't even showing up, so I am showing it with ShowWindow(hTaskbar, SW_SHOW). When it shows up, everything works when I click on the icons of other applications, so there must be something wrong with mine, but I am not sure where to start.

You need to handle WM_SYSCOMMAND and respond to SC_MINIMIZE.
WM_SYSCOMMAND on MSDN

Related

Showing a QMessageBox breaks QLineEdit highlighting

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);

Custom Touch behavior in Windows 7 with Qt/QML application

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().

QDesktopWidget and windows taskbar

I need to have app running in fullscreen mode.
For that I used QDesktopWidget. When windows taskbar is lock it work fine.
Problems start when taskbar is in auto-hide mode.
I cannot find any way to receive information (signal), that taskbar size on desktop changed,
so I cannot react and change my widget size.
Is there any way to obtain information that windows taskbar changing from hidden to visible or opposite?
I would be glad about any hints.
Marek
I don't know why you use QDesktopWidget for running in fullscreen mode! You can simply set your MainWindow state to fullscreen by :
this->setWindowState(Qt::WindowFullScreen);

hide system cursor in system wide

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.

In some windows, ctrl key will exit Flex app full screen mode

I have one flex app which supports full screen mode. In some machine, it looks fine, click "Esc" could quit the full screen mode. And I could use "Ctrl-C" to copy some text.
But in some machine, pressing "ctrl" key will exit the full screen mode. Then the mouse action become sticky, when I move popup screen via drag popup title, it keep moving even after I release mouse.
The problem sometime happen in the same machine which used to work fine. I am feeling that could be a flex defect.
Any suggestion?

Resources