The QtUiTools module classes can be included using the following directive:. In a class that uses QtUiTools to build its user interface at run time, we can locate objects in the form using QObject::findChild. For example, in the following code, we locate some components based on their object names and widget types:.
Processing forms at run-time gives the developer the freedom to change a program's user interface, just by changing the UI file. This is useful when customizing programs to suit various user needs, such as extra large icons or a different colour scheme for accessibility support.
The signals and slots connections defined for compile time or run time forms can either be set up manually or automatically, using QMetaObject 's ability to make connections between signals and suitably-named slots. Generally, in a QDialog , if we want to process the information entered by the user before accepting it, we need to connect the clicked signal from the OK button to a custom slot in our dialog.
We will first show an example of the dialog in which the slot is connected by hand then compare it with a dialog that uses automatic connection. We define the dialog in the same way as before, but now include a slot in addition to the constructor:. In the dialog's constructor we set up the widgets as before, and connect the Cancel button's clicked signal to the dialog's reject slot. We also disable the autoDefault property in both buttons to ensure that the dialog does not interfere with the way that the line edit handles return key events:.
We connect the OK button's clicked signal to the dialog's checkValues slot which we implement as follows:.
This custom slot does the minimum necessary to ensure that the data entered by the user is valid - it only accepts the input if a name was given for the image. Although it is easy to implement a custom slot in the dialog and connect it in the constructor, we could instead use QMetaObject 's auto-connection facilities to connect the OK button's clicked signal to a slot in our subclass.
Using this convention, we can define and implement a slot that responds to mouse clicks on the OK button:. We use QMetaObject 's system to enable signal and slot connections:.
Automatic connection of signals and slots provides both a standard naming convention and an explicit interface for widget designers to work to. By providing source code that implements a given interface, user interface designers can check that their designs actually work without having to write code themselves. Documentation contributions included herein are the copyrights of their respective owners.
Qt and respective logos are trademarks of The Qt Company Ltd. All other trademarks are property of their respective owners. At runtime , which means that forms are processed by the QUiLoader class that dynamically constructs the widget tree while parsing the XML file.
Compile Time Form Processing You create user interface components with Qt Designer and use Qt's integrated build tools, qmake and uic , to generate code for them when the application is built. A member function called setupUi to build the widget tree on the parent widget. A member function called retranslateUi that handles the translation of the string properties of the form.
For more information, see Reacting to Language Changes. A compile time processed form can be used in your application with one of the following approaches: The Direct Approach : you construct a widget to use as a placeholder for the component, and set up the user interface inside it.
The Single Inheritance Approach : you subclass the form's base class QWidget or QDialog , for example , and include a private instance of the form's user interface object. The Multiple Inheritance Approach : you subclass both the form's base class and the form's user interface object. PySide2 was announced recently and got me interested in trying to use it to load up a UI file. This is actually very similar to the way you would create an interface using Visual Studio.
Then I chose the "Qt Widgets Application" choice. See screenshot below:. Then I opened up the mainwindow. You can just double-click it or click on the Design button that should be on the left-hand side of the program.
Qt notifies applications if the user interface language changes by sending an event of the type QEvent::LanguageChange. To call the member function retranslateUi of the user interface object, we reimplement QWidget::changeEvent in the form class, as follows:. Alternatively, forms can be processed at run time, producing dynamically- generated user interfaces. A resource file containing a UI file is required to process forms at run time.
Also, the application needs to be configured to use the QtUiTools module. This is done by including the following declaration in a qmake project file, ensuring that the application is compiled and linked appropriately.
The QUiLoader class provides a form loader object to construct the user interface. This user interface can be retrieved from any QIODevice , e. The QUiLoader::load function constructs the form widget using the user interface description contained in the file.
The QtUiTools module classes can be included using the following directive:. In a class that uses QtUiTools to build its user interface at run time, we can locate objects in the form using qFindChild. For example, in the follownig code, we locate some components based on their object names and widget types:.
Processing forms at run-time gives the developer the freedom to change a program's user interface, just by changing the UI file. This is useful when customizing programs to suit various user needs, such as extra large icons or a different colour scheme for accessibility support. The signals and slots connections defined for compile time or run time forms can either be set up manually or automatically, using QMetaObject 's ability to make connections between signals and suitably-named slots.
Generally, in a QDialog , if we want to process the information entered by the user before accepting it, we need to connect the clicked signal from the OK button to a custom slot in our dialog. We will first show an example of the dialog in which the slot is connected by hand then compare it with a dialog that uses automatic connection.
We define the dialog in the same way as before, but now include a slot in addition to the constructor:. In the dialog's constructor we set up the widgets as before, and connect the Cancel button's clicked signal to the dialog's reject slot. We also disable the autoDefault property in both buttons to ensure that the dialog does not interfere with the way that the line edit handles return key events:. We connect the OK button's clicked signal to the dialog's checkValues slot which we implement as follows:.
This custom slot does the minimum necessary to ensure that the data entered by the user is valid - it only accepts the input if a name was given for the image. Although it is easy to implement a custom slot in the dialog and connect it in the constructor, we could instead use QMetaObject 's auto-connection facilities to connect the OK button's clicked signal to a slot in our subclass.
Using this convention, we can define and implement a slot that responds to mouse clicks on the OK button:. We use QMetaObject 's system to enable signal and slot connections:.
Automatic connection of signals and slots provides both a standard naming convention and an explicit interface for widget designers to work to. By providing source code that implements a given interface, user interface designers can check that their designs actually work without having to write code themselves.
Documentation contributions included herein are the copyrights of their respective owners. Qt and respective logos are trademarks of The Qt Company Ltd. All other trademarks are property of their respective owners.
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