Maybe I'm thinking about this completely wrong...
I've created a new widget in Qt Creator with a Designer file (I picked the Widget template, which generated a source and header file for my custom widget class, and also a designer file).
I then designed the widget with the Designer. I can now create instances of this widget and it will show up in my app.
But it's not terribly useful because I don't know how to customize the widget at runtime.
Let's say all I've got in the widget is a Label and a Button. At runtime, how can I change the text of this label? I can't figure out how to connect the designer stuff to my actual class, and I can't find any documentation on how to do this. Am I missing something?
Thanks!
A few things:
In designer, each of your widgets (the QPushButton, and the QLabel in your case) has a name assigned to it. This name is the name of the variable that you can use in C++ to reference that widget and call functions on it.
Depending on how your custom widget was implemented, you will be able to reference these variables using one of two methods:
If your class inherits from Ui::MyCustomwidget, then your variables are simply member variables of your class and can be accessed at any time (myLabel->setText())
If you have a member variable (generally named ui, of type Ui::MyCustomWidget), then you can access your widgets using the ui object (ui->myLabel->setText())
Related
I have created custom dialog class that inherits from QDialog. I would like to use it in a Qt Designer.
However there is a problem, as I do not know how to add it to the templates, that I could pick, when I select File/new.
I also tried to start with QDialog and then promote it to my custom class, however context menu on the form does not give me option to promote or change type of the form.
Is there a solution to this problem which does not include manually tweaking generated .ui file ?
I have a graphical application written in C++ using Qt for an embedded device, which uses a QStackedWidget holding a number of UI widgets. The UI is all designed in Qt Creator's designer tool. When the user navigates through the device's application the display to be shown at that menu option is selected from the QStackedWidget and this all works great.
I'm now wanting to pass in a pointer to some configuration which is read from file when the application starts, but I can't seem to find a way to pass this pointer as an argument into the constructor of a widget on the QStackedWidget. Can anyone help?
My current approach is to call a function I've written within the class of a widget on the QStackedWidget, which works but doesn't feel the best way to do it.
To my knowledge if you want to use custom constructors - with other kinds of arguments than just the QWidget * parent - you have to create the ui programmatically:
create your custom StackedWidget with a special constructor,
prepare the global interface using the designer,
then add the StackedWidget in the constructor of the class after the setupUi method.
The other way is to use an initialization method after the construction of the item, like you did.
I got a external library, which includes a derived class from QGLWidget, very similar to that one here. In that library I have a class:
class PictureGLWidget : public QGLWidget { //.. }
This extends Qt's native QGLWidget and personalizes it. But it was not written by me, I just got it, via a *.dll. So then, I bind that Widget manually in my code to a layout like:
QGridLayout* layout = new QGridLayout;
layout->addWidget(myPictureGLWidget, 0, 1);
ui->verticalLayout_5->addLayout(layout);
since I designed my MainWindowWidget with the integrated QtDesigner, which is by the way very comfortable, I would like to handle my myPictureGLWidget also in the QtDesigner, since I am currently redesigning the MainWindow.
Is there a way doing that? Thnx in advance!
Qt Designer supports any foreign widget class without needing to provide plugins for that. You only have to accept that the widget's properties and appearance won't be available within Designer.
Insert a dummy QWidget into the layout.
Right click on the widget, select "Promote to...".
Add PictureGLWidget as a new class promoted from QWidget. Specify appropriate header files etc.
Promote your widget to PictureGLWidget.
When this is done, the code generated by uic will instantiate a PictureGLWidget where you need it, instead of a dummy QWidget.
If you want to use the PictureGLWidget in the designer instead of a dummy widget, you can write a designer plugin that wraps the widget and exposes it in the widget pallette, provides property support, etc.
I might have misunderstood your question but don't you just add a QGLWidget to your design in Designer. Right click the widget and select Promote to... ?
I made a form using the Qt Designer which has some dockwidgets, these dockwidgets have some children widgets. How I can access the dockwidget and these child widgets in my mainwindow.cpp?
I highly recommend reading the docs for these kinds of things, but to give you a little head start, QDockWidget inherits from QWidget, which inherits from QObject:
https://doc.qt.io/qt-4.8/qobject.html#children
widget->children() would simply tell you the children of this widget. This would be needed if you didn't already know the names of the objects to be accessed directly, or had no reference to them.
Update
When you create objects in Qt Designer, and you run the setupUi(this) that is generated for you, inside of your MainWindow, you will then have access to all of the widgets you had set up as members. You can access them directly as they were named in Qt Designer. Please check out one of the numerous tutorials on getting started with Qt. Here is one that shows you how to make use of your ui file, and access the members from it: http://sector.ynet.sk/qt4-tutorial/my-first-qt-gui-application.html
You can also get a list of all the dockWidgets from the mainwindow with
QList<QDockWidget *> dockWidgets = findChildren<QDockWidget *>();
A similar technique works for getting toolbars etc. so you don't have to manually store a list as you create them
I've subclassed qt's pushbutton and now I would like to use it in my project (instead of qpushbutton) - the problem I have is that even if I add #include "mybutton.h" in ui_class it gets overwritten and I don't know what else can I do it.
Is there a way to have this button within designer on a panel just like the ordinary qpushbutton is?
Never modify the ui_Class file yourself. Any change you make there will be overwritten when the .ui gets compiled. Instead use the promote to functionality within QtDesigner.
If some forms must be designed, but certain custom widgets are
unavailble to the designer, we can substitute similar widgets to
represent the missing widgets. For example, we might represent
instances of a custom push button class, MyPushButton, with instances
of QPushButton and promote these to MyPushButton so that uic generates
suitable code for this missing class.