main.qml

import QtQuick 2.6
import QtQuick.Controls 1.5

ApplicationWindow {
    id: applicationWindow
    visible: true
    width: 640
    height: 480

    Label {
        id: helloLabel
        height: 50
        anchors {
            top: parent.top
            left: parent.left
            right: parent.horizontalCenter
            margins: 10
        }
    }

    ComboBox {
        id: comboBox
        anchors {
            top: parent.top
            left: parent.horizontalCenter
            right: parent.right
            margins: 10
        }

        model: ["ru_RU", "en_US"]

        // If you change the text, initialize the translation unit via C++ Layer
        onCurrentTextChanged: {
            qmlTranslator.setTranslation(comboBox.currentText)
        }
    }

    Label {
        id: labelText
        wrapMode: Text.Wrap
        anchors {
            top: helloLabel.bottom
            left: parent.left
            right: parent.right
            margins: 10
        }
    }

    // Connect to an interpreter object
    Connections {
        target: qmlTranslator // was registered in main.cpp
        onLanguageChanged: {
            // upon receipt of the signal to change the language
            retranslateUi() // initialize interface translation
        }
    }

    // interface translation function
    function retranslateUi() {
        applicationWindow.title = qsTr("Hello World")
        helloLabel.text = qsTr("Hello World")
        labelText.text = qsTr(
                    "The QTranslator class provides internationalization"
                    + "support for text output.An object of this class contains "
                    + "a set of translations from a source language to a target language. "
                    + "QTranslator provides functions to look up translations in a translation file. "
                    + "Translation files are created using Qt Linguist.")
    }

    // Start translating the application window when the application was created
    Component.onCompleted: {
        retranslateUi()
    }
}