Exploring Qt Quick Controls 2: Building Modern User Interfaces

Qt Quick Controls 2 is a powerful module in the Qt framework that allows developers to create stylish and responsive user interfaces for desktop and mobile applications. In this blog post, we will dive into the key features of Qt Quick Controls 2 and explore how to use them to build modern UIs. We’ll also provide code snippets to illustrate the concepts discussed.

1. Installing Qt Quick Controls 2: To begin, make sure you have Qt installed on your system. Qt Quick Controls 2 is included in the Qt framework. You can download Qt from the official Qt website (https://www.qt.io/download).
2. Importing the Qt Quick Controls 2 module: To use Qt Quick Controls 2 in your application, you need to import the module in your QML file. Add the following import statement at the beginning of your QML file:

import QtQuick.Controls 2.15

3. Basic Usage of Controls: Qt Quick Controls 2 provides a variety of ready-to-use UI controls. Let’s start with a simple example using a Button control:

import QtQuick 2.15
import QtQuick.Controls 2.15

ApplicationWindow {
    visible: true
    width: 400
    height: 300

    Button {
        text: "Click me!"
        onClicked: {
            console.log("Button clicked!");
        }
    }
}

You can find all available QML types here: https://doc.qt.io/qt-6.2/qtquick-controls2-qmlmodule.html.

4. Customizing Controls: Qt Quick Controls 2 allows you to customize the appearance of controls implementing the built-in background and contentItem properties. Here’s an example of customizing a Button control:

Button {
    id: openDialogBtn
    width: 120
    height: 30
    background: Rectangle {
        color: openDialogBtn.pressed ? "#298fca" : "#0079bf"
        opacity: .7
    }
    contentItem: Item {
        Label {
            anchors.centerIn: parent
            color: "#171717"
            text: openDialogBtn.text
        }
    }
    onClicked: {
        confirmationDialog.open();
    }
}

MessageDialog {
    id: confirmationDialog
    title: "Confirmation"
    text: "Are you sure you want to delete?"
    onAccepted: {
        console.log("Delete confirmed!");
    }
    onRejected: {
        console.log("Delete canceled!");
    }
}

Note that contentItem and background items inherit automatically the control’s sizing so there is no need to be setting width/height or anchors.fill: parent properties. If both or either contentItem and background properties are not implemented, then the control will fall back to it’s default style (https://doc.qt.io/qt-5/qtquickcontrols2-default.html).

Qt Quick Controls 2 is a powerful module that simplifies the process of building modern user interfaces in Qt applications. We’ve explored the basics of importing the module, using controls, customizing their appearance, and working with dialogs. By leveraging the capabilities of Qt Quick Controls 2, you can create visually appealing and interactive UIs for your applications.

Remember to refer to the official Qt documentation (https://doc.qt.io/qt-5/qtquickcontrols2-index.html) for the API provided by the Qt Quick Controls 2. Happy coding!