I have my custom widget inherited from QWidget, and I've connected the widget's menu-calling signal to my slot.
connect(m_ontologyView, SIGNAL(customContextMenuRequested(QPoint)), SLOT(showContextMenuSlot(QPoint)));
Now I want user to be able to change button calling the context menu. Normally it's called with right mouse button, but how do I tell the widget to call the menu with a button of my choice?
I'm on Qt 5.4.0
Instead of using QWidget::customContextMenuRequested, you will need to reimplement the widgets mouse event functions, QWidget::mousePressEvent, QWidget::mouseReleaseEvent and QWidget::mouseMoveEvent. Inside of these events, you can then show you menu using QMenu::popup. (The point can be extracted from the mouse events).
Related
In QMainWindow, when few widgets are tabbed together in dock area, how can I detect when a tab has been toggled by user? It is not a problem when I have an instance of QTabWidget created by myself and can attach a handler to currentChanged(), but what's about this case when the main window internally performs docking/tabifying operations? It normally would be showEvent() triggered but by some reason it doesn't work when tabs are switched. Also, a widget, not on active tab, has it's visibility state turned ON (isVisible() returns true) which is strange.
I found the answer. It is QMainWindow::tabifiedDockWidgetActivated() which is signaled when a tab on a docked widget changes. It was added in Qt 5.8. Without it there is no way.
I am programming in C++ in QT and trying to make a UI with dynamic tabs having tables inside each of them. For doing the same, I had my TabWidget in the main window, and another widget with just the tableView. As the tabs are dynamically being added to the main window by a button click, I make a new object of my widget and put it in that.
I also have another version of the application in which there are no tabs, just a tableView in the main window.
I am unable to open the context menu in the former case, while it works perfectly for the latter.
I am using the signal "customContextMenuRequested" in both the cases. Don't understand what I need to add for it to work when the tableView is in a child widget.
Some help please?
Thanks already!
Did you check that nothing is involving QAbstractScrollArea, it's possible that in this case it would signal/slot as expected.
This signal is emitted when the widget's contextMenuPolicy is Qt::CustomContextMenu, and the user has requested a context menu on the widget. The position pos is the position of the context menu event that the widget receives. Normally this is in widget coordinates. The exception to this rule is QAbstractScrollArea and its subclasses that map the context menu event to coordinates of the viewport() .
I have created 2 *.ui using Qt Designer in my project, where one is the main screen and another one is a dialog widget. The dialog widget is called by one of the functions in main screen.
How can I connect the function in my main window to call the dialog widget?
e.g. If I click on [About > Author] in my main window's menu, I should be able to call the dialog widget.
Any help will be appreciated.
Thanks.
It depends on where you keep your dialog pointer. For example, you can create some signal on your main window and connect it with dialog show() slot(or exec() if you need it to be modal).
Or if you keep your dialog pointer in the main windows then you can just use it with show/exec method directly.
As to About->Author menu: for that you should create QAction and add it to the menu. And QAction has triggered() signal which you can connect to exec/show slot of the dialog.
I have a simple parent widget that reimplements mousePressEvent/mouseReleaseEvent. The parent's child widgets use enterEvent/leaveEvent. When I hover the mouse over the child widgets, leaveEvent/enterEvent executes, but when I click and hold the mouse, mousePressEvent executes, but enterEvent/leaveEvent goes silent (in other words, no click and drag). Any ideas about what could be causing this?
If you press and hold down the mouse button on a widget then that widget grabs mouse events until you release the button. This is not a special feature of Qt, you can find similar behaviour in every other GUI APIs I know.
Take a look at the relevant part of the Qt documentation:
QWidget / Events:
mousePressEvent() is called when a mouse button is pressed while the
mouse cursor is inside the widget, or when the widget has grabbed the
mouse using grabMouse(). Pressing the mouse without releasing it is
effectively the same as calling grabMouse().
void QWidget::grabMouse ():
Grabs the mouse input. This widget receives all mouse events until
releaseMouse() is called; other widgets get no mouse events at all.
I've recently been studying Qt, and have the following questions:
What is the difference between QAction and QToolButton?
How do I know when to override QPushButton? For example, should I override in order to be informed when the mouse enters a QPushButton's bounds? I don't need to in order to get the signal click().
Question 1:
QActions are used to define tasks performed by an application in a way which can be understood by a number of different user interface objects. Using an example from the Qt docs for context:
A QAction is defined; it is given an icon image, a text description, a keyboard shortcut and a longer tooltip description, as well as being linked to a user defined function.
newAct = new QAction(QIcon(":/images/new.png"), tr("&New"), this);
newAct->setShortcuts(QKeySequence::New);
newAct->setStatusTip(tr("Create a new file"));
connect(newAct, SIGNAL(triggered()), this, SLOT(newFile()));
Later in the implementation, the QAction is added both to a textual menu bar...
fileMenu->addAction(newAct);
... and an icon-based tool bar:
fileToolBar->addAction(newAct);
The menu bar uses the text description to create an entry in the menu corresponding to the action. Similarly the toolbar uses the icon set on the QAction to create an icon in the toolbar which corresponds to the action. Selecting the menu item, clicking the toolbar icon or pressing the keyboard shortcut will all result in the same effect: that defined by the linking of QAction::triggered() to newFile().
So to directly answer your question: a QAction is an abstract way of defining the various parameters and behaviour of a particular task performed by the application. A QToolbarButton is a UI object (derived from QWidget) created by a QToolbar in response to QToolbar::addAction()
Question 2:
Yes, QPushButton has a clicked() signal inherited from QAbstractButton, but it does indeed lack a way to inform when the mouse has entered its bounds. You have a couple of options in order achieve this, but first you need to first set the mouseTracking property to be enabled. This will allow you to receive mouse move events on the QPushButton even if no mouse buttons are pressed. With that done you need to explore one of the following options:
As you suggest, you could subclass QPushButton and reimplement mousePressEvent in order to respond to the mouse position.
You could install another widget as an eventFilter on the QPushButton, and watch for events of type (QEvent::MouseMove).