I have a widget container I wish to manually paint.
However, it is located within my GUI's MainWindow class.
Is there any way I can register on the paint event for a specific QWidget, so my own function will be called ?
Look for eventFilter. It will help you
The most straightforward way would be to override the paintEvent on the widget
you would like to draw in a custom subclass, and then use that class in your GUI.
Related
I have setup my app to have various dock windows within the main window. I am also able to add a toolbar to the main window. However, I would ideally like to add the QToolBar inside one of the QDockWindow instances (or the QWidget that it houses) as the toolbar will be specific to that window.
Is this possible? I'm using a recent version of Qt, 5.10.
I think it is possible.
1.QDockWidget can set a QMainWindow by setWidget() method.
QMainWindow is made for just a mainwindow but it is not prevented from being used as a subwidget.
2.QToolBar can be attached to the main-subwindow by addToolBar() method.
3.The subwidget-mainwindow can naturally have its own QToolbar.
If you don't want to use QMainWindow as the widget of its QDockWidget,you can attach the QToolBar as a child widget of QDockWidget. But The toolbar is not movable as QMainWindow's.
I think you want to add QToolBar and use it as QMainWindow.
So I recommend that you set a QMainWindow as the widget of QDockWidget.And you attach any widget you like to the mainwindow after that.
I'm new to Qt programming and I am developing a drawing application. I have a class MyWidget which has a member QGraphicsView. MyWidget is a member of another class MainWidget (which has other widgets as well and all of them are in a layout).MainWidget is the central widget of my subclass of QMainWindow.
I have created functions to scale the view with the mouse wheel event and a function to drag the scene around.
The problem is - I want to set the Scene's size to be fixed, and to be 3 times the size of the view, but since the view is managed by a layout in order to take as much space as possible I can't get the view's size?
Any help appreciated.
the size property will give you the current size of your widget:
http://qt-project.org/doc/qt-4.8/qwidget.html#size-prop
Alternatively, you could subclass QGraphicsView and re-implement the resizeEvent:
http://qt-project.org/doc/qt-4.8/qwidget.html#resizeEvent
For a full example, have a look into:
http://qt-project.org/doc/qt-4.8/widgets-scribble.html
You can definitely get the view's size. There are two ways to go about it:
Attach an event filter object to your view: myView->installEventFilter(filterObject). The filterObject's eventFilter method will be invoked for all events reaching your view, including resize events.
Use a custom view class and reimplement resizeEvent. This method gets called each time the widget is resized. Do note that designer allows you to add custom classes without having to write plugins.
I think i'm having a fairly basic Qt problem, but i can't figure it out:
I have a QMainWindow which holds a QStackedWidget. All page widgets in there are seperate classes derived from QWidget.
So:
QMainWindow implements QStacked Window in one class.
All other pages inside the stacked widget are added classes and all have there own .ui filled with buttons and lists trough the Designer.
For navigating to different pages, inside the Mainwindow i have access to: ui.stackedWidget->setCurrentIndex(2);
It seems i don't have access to ui.stackedWidget on another page inside the stacked widget? I have no access to the ui.stackedWidget because Ui is a private member in the mainwindow class. (auto generated by Qt - using VS addon for adding QT4 classes)
I would like to know, how can i jump to another page in the stacked widget, when clicking on a button that belongs to another page inside this widget?
Note:
All pages are added to the StackedWidget in mainWIndow's constructor:
ui.stackedWidget->addWidget(page1Widget);
ui.stackedWidget->addWidget(page2Widget);
// etc..
Example of a button click signal-slot inside page1Widget:
connect(ui.btnViewData, SIGNAL(clicked()), this, SLOT(viewData()));
::viewData()
{
// navigate to another page here.
// note: ui.stackedWidget->setCurrentIndex(3); is not accessible here!
}
I believe that putting your connect() and viewData() functions within your QMainWindow object will solve your problem, since the main window can have access to both the signals emited by the child widgets and the QStackedWidget items.
You might need to write a Ui getter for each of your page, and then do something like
connect(page1Widget->getUi().btnViewData, SIGNAL(clicked()), this, SLOT(viewData)));
hope it helps,
cheers
I have a QListWidget and I have set it to accept drops, the mode to be DragDrop etc and I can move QListWidgetItems all around the place (inside the QListWidget of course).
I like this behavior and I want it to let it as is, but I also want my QListWidget to accept drops from a QTreeWidget as well. If I attempt to reimplement the dropEvent() of my QListWidget then I lose the default behavior.
Is there any way to just extend the current behavior so as to have both drag-drop between listwidget items and drag-drop from the treewidget to the listwidget or I have to completely re-write both behaviors in my dropEvent() reimplementation?
Thanks a lot for any answers :)
Two ways:
implement a standalone event filter and make it act upon QEvent::Drop. Install it on your original QListWidget. Return false so that the original dropEvent() handler is called afterwards.
inherit from QListWidget, reimplement dropEvent(evt) and as a last statement, call QListWidget::dropEvent(evt);. Your original behavior will be retained.
No.
Subclass QListWidget, reimplement
virtual void QListWidget::dropEvent ( QDropEvent * event )
and explicitly call
QListWidget::dropEvent(event);
whenever you need the default behavior.
How to call a parent class function from derived class function?
i'm quite new to Qt and i've a question.
I've got an application with multiple windows/QFrame. I'd like them to only exist within the mainwindow (it's also the parent gadget). When I move them, I want the to stay within the parent gadget.
Is is possible ?
If yes, how ?
I've been through the Qt doc and i've found nothing. I though maybe a simple option can do that. Or do I have to create a new Widget with customs mouse Event methods ?
Thx
If you want a Multiple Document Interface (MDI) GUI you can use the QMdiArea and QMdiSubWindow classes to implement this. Have a look at the detailed description section of QMdiArea for using it with a QMainWindow example, but it also works on any other widget as well.