In my Qt application, I have couple of QtWidgets which are floating. I want to know when QtWidget is dragged to another screen So that I can resize content within according to new screen DPI.
Connect the primaryScreenChanged signal from your QGuiApplication to slots in your widgets.
Edited to add: On reflection, this probably doesn't do what you want -- it signals when the application changes screen, not the widget.
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I have a QtWidgets application in which I need virtual keyboard in. Currently, I put it inside a QQuickWidget inside the app.
My problem is that sometimes, I dynamically need to add QWebEngineView widget, to play some video from web source. The problem is that Virtual keyboard leaves the QQuickWidget and jumps to the QWebEngineView.
When I delete (dynamically) this widget after being used, virtual keyboard doesn't return to the QQuickWidget again.
I tried to search a lot about what can be reason. but I cannot find anything
So, mainly the question is how to force Qt virtual keyboard to be in the QQuickWidget and not leave it?
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 have an application in Qt in which I can switch between c++ app and QML app (setting central widget to one or other).
The problem is that in order to work this, I had to change my main.qml from ApplicationWindow to Page and now Dialogs and all Popups in my QML app are not working properly (modality and focus is not working at all).
My code looks like that:
QQuickWidget *view = new QQuickWidget(this);
view->setSource(QUrl(QStringLiteral("qrc:/main.qml"))); //Page
MyCppApp *myCppApp = new MyCppApp (this); //QWidget
QStackedWidget *stackedWidget = new QStackedWidget;
stackedWidget->addWidget(view);
stackedWidget->addWidget(myCppApp);
stackedWidget->setCurrentIndex(1);
setCentralWidget(stackedWidget);
I know in Popup's documentation there is that "It can be used with Window or ApplicationWindow." but is there a way to get Popups in my QML work properly?
I am using Qt 5.8 and Qt Quick Controls 2.
For the modality you should not make the dialog window part of central widget in main window (otherwise it is modal relative to what?). Invoke it from main window. And to give it modal dialog looks and behavior you can apply window flags like that:
// this view is not a part of the app main window
view->setFlags(Qt::Dialog | Qt::WindowTitleHint |
Qt::WindowStaysOnTopHint | Qt::MSWindowsFixedSizeDialogHint);
Mind that Qt::MSWindowsFixedSizeDialogHint is of course applicable on Windows only. And for setting the focus:
// to set the edit focus such trick needed
QTimer::singleShot(0, view, SLOT(setFocus()));
I use that with QML widget container. Implementation details may differ. And no QML part visible. There you may need to take care of FocusScope then.
The only window in my application is a QQuickView which is a subclass of QWindow, not of QWidget, so if I want to use a QFileDialog to give the user the option to save a file, I do not know how to set its parent to be the QQuickView. I know that the QFileDialog works without a parent, but if it does not have a parent, it is not centered over the QQuickView. This is not a big problem on its own, but on my OS (Ubuntu 13.10) a QFileDialog without a parent sometimes appears under the QQuickView window and the user sees only a “flashing” taskbar icon.
I use Qt 5.2. I initially tried to use the FileDialog type in the Qt Quick Dialogs module but it does not have some features I need (such as the defaultSuffix property).
Right, this is a serious problem of QML. You cannot utilize the QFileDialog because you don't have a QWidget app and FileDialog lacks some critical features.
See: FileDialog in QTQuick (QML): Save file under given name
At the moment we are using code from deep down in the Qt source code, which is not in the public API. It only requires a Window instead of a Widget to do modality right.
Maybe I can write a blog post about that over Christmas.
My app loads a plugin which creates a window (QWidget), but I can not destroy it when I exit from QMainWindow, obviously because widget returned from plugin is not a child of QMainWindow. The issue is that if I make that window to be a child of mainwindow, I get a window on another window. But I need them both to be separated. I did them separated (but main window has no control over window from plugin), in my case I do not know how to close window from plugin when app quits. How can I achieve that?
Just delete it. If you don't assign it a parent, no other widget has ownership. So you should simply be able to destroy it yourself on exit.