qsystemtrayicon opens many windows , need one - qt

When clicked multiple times, a qsystemtrayicon should open only once. How is it possible?

That's up to you handle how many instances of a Window are fired up. QSystemTrayIcon has nothing to do with it. You most probably are creating a widget each time the system tray icon is clicked, instead of using just one and calling QWidget::show() and QWidget::hide() respectively. That's the best shot i can take at your issue, given the thin description.

Related

How to catch all and only button release events in Qt?

My team is developing an UI for an apparatus with touch screen and we would like it to emit a sound (from a buzzer) each time the user correctly presses a button (so using the release event). Notice that I don't want to play the sound after each click on the interface, but only when the click is over a button.
We use many types of button, sometimes QPushButton and most of the times customized buttons derived from QAbstractButton. In most cases these buttons get an objectName.
So I supposed in order to do that, I would have to catch the MouseButtonRelease event and since I'm already working with a subclass of QApplication to handle excetions, I decided to do this in the notify function.
I tried, then, some methods to recognized when the MouseButtonRelease was related to a button but none of them were successfull. The best one, verifying the receiver's objectName was still not good enought not only because not all buttons had an objectName (which, of course, can be handled), but specially because not always the event was caught for buttons with names set. In other words, sometimes I would click in a button and it recognizes the event and sometimes I would click in the same button and the event is not recognized.
I did some research and another method I found was to set an event filter in the MainWindow, but not all widgets have the MainWindow as their parent which means I would have to Ctrl+c / Ctrl+V the same code time after time when I obviously want something more localized (i.e. in only one spot).
So why it happens that the notify not always handles the events? And how could I do this? Any suggestions are appreciated specially one that is less heavier then handling the events globally.
As info, the other two ways I tried to catch the events with similar or even worst results inside notify were with receiver->inherits("...") and qobject_cast< QAbstractButton* >(receiver).

Mouse button status

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.

QSystemTray problems

I am trying to use QSystemTrayIcon for my application and i am facing some problems.
It is the first time i use qt so i am not really used to it.
I followed this tutorial to make a system tray icon but i fail to customize it.
I want to have a button show/hide and not 3 show, hide, restore. These actions are really confusing for a newbie and i dont know what to do and what to connect.
I tried some things but with no luck.
Also when the system tray menu appears if you click somewhere else, the menu stays open.
Any way to solve this thing too?
If you want to remove one of the menu items, modify the createTrayIcon function so that it only adds the actions you need (and clean up the unused members once you get it to work). It's that simple.
If you want a single menu item or button to toggle between visible and hidden, you'll need to create a custom slot that calls show() or hide() (or setVisible(bool)) depending on whether the widget is hidden or not (use isVisible() for that for example). Then connect your action to that slot.
Read the Signals and Slots documentation and examples for information about how to create a new slot.

A real top level window with Qt?

I use the last Qt version for a projet and QProcess. I want to lauch program from my application by using QProcess. I want to display a QGraphicsView transparent on full screen over the launched program.
For the moment: I hide the view, launch the program, sleep during 5 seconds and show the view. I want that my view keep the focus and stay on the top level? Is there any better way to do that? A custom setting for the QGraphicsView?
Create your QGraphicsView (or the window that contains it) with the Qt::WindowStaysOnTopHint flag
Once you run a program in QProcess, you have limited control over it. Qt does not provide details about other applications that are running, you won't know where the launched application is being displayed unless it tells you explicitly.
If you have access to the code of the application you're running, it is possible put a transparent overlay on top a given widget, or widgets, that could then record mouse clicks and other interactions. It's also possible to override events and record basic information about the application's use.

Attach Qt windows?

Is there any way to attach two Qt windows together? For example, if window A is the main window and window B is another widget I want to be able to show window B to the side of A and have both windows move together if the windows are dragged.
Not that I am aware of, but you can try following the trail of QMoveEvent. When a given widget is moved void QWidget::moveEvent ( QMoveEvent * event ) is called, and the QMoveEvent contains both old and new pos. Using this information, you can inject a move event in the other widget as well, and make it follow.
Of course, I am speaking of two independent widgets, each one in its own window. If they are contained, you don't need anything but a Layout management (see QLayout and related classes).
I don't work with Qt since a long time, so there could be a better method, but if I had to do it right now, this is the strategy I would use.
Also, I have the feeling that the QMoveEvent will be invoked only at start and end, unless you enable mouse tracking. If the former is the case, you will obtain that the other widget will "teleport" at the end of the move, instead of following smoothly.
You might be after something like this:
http://doc.qt.io/archives/4.6/qt4-mainwindow.html
Window A would be a QMainWindow and window B would be a QDockWidget.

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