Usage of QString in QML

sush123

Hi Everyone,

I need to use QString in QML can anyone help me how can i use the same

J.Hilk

@sush123
please some more information on what you want to actually do, and tell us what you already tried.

ODБOï

@sush123
Qt Type 'QString' is converted to QML Basic Type 'string' automatically
https://doc.qt.io/qt-5/qtqml-cppintegration-data.html#basic-qt-data-types

sush123

@J-Hilk

i have a class ABC.cpp which has function called Test(QString index) looks like
void ABC :: Test(QString index).

In XYZ.qml i am trying to access above in qml like

ABC.Test("Hello"); -> works fine but

when i declare that in constants.qml like

readonly property string TXT_HELLO: "Hello"

and use as below
ABC.Test("Constants.TXT_HELLO");
it doesnot work where i am wrong.

Pradeep P N

@sush123

You already have the property so you can use it directly in your function without" "
ABC.Test(TXT_HELLO);

can you please tell us what is Constants you are referring to ?

Below is some sample code...

TestString.h :

public slots:
    void printQmlString(const QString &str);

TestString.cpp:

void TestString::printQmlString(const QString &str)
{
    qDebug() << Q_FUNC_INFO << str << endl;
}

main.cpp:

TestString ts;
engine.rootContext()->setContextProperty("TS", &ts);

QML:

import QtQuick 2.6
import QtQuick.Window 2.2

Window {
    id: root

    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    readonly property string myString: 'Hallo Qt, :)'

    /*  ...*/

    Component.onCompleted: TS.printQmlString(root.myString)
}

Output:

All the best.

sush123

@Pradeep-P-N

i am sorry i will be more clear now :

ABC class has a function called toolbarButtonClick:
void ABC::toolbarButtonClick(QString index)
{

}

Constants.qml is a file where i am thinking to keep all the strings at one place
looks like :

import QtQuick 2.0
pragma Singleton

QtObject {
readonly property string TXT_HELLO: "Hello"
readonly property string TXT_WORLD: "World"
}

For ToolbarButton i need to have Buttonclick
ToolbarButton {
label: qsTr("toolbutton")

onButtonClick: {
ABC.toolbarButtonClick(Constants.TXT_HELLO)
}
onButtonLongPress: {
ABC.toolbarLongPress(Constants.TXT_HELLO)
}
}

When i use like above i dont get click event

if i use directly strings like below it will take click event
onButtonClick: {
ABC.toolbarButtonClick("Hello")
}
onButtonLongPress: {
ABC.toolbarLongPress("Hello")
}

Pradeep P N

@sush123 said in Usage of QString in QML:

Constants

Please tell me do you have any error on buttonClick() & buttonLongPress() ?

something like below :
ReferenceError: Constants is not defined

Pradeep P N

@sush123

Please register your Constants.qml singleton before you use it.

refer qmlRegisterSingletonType - QQmlEngine Class.

below is sample code for the solution:

main.cpp

    qmlRegisterSingletonType(QUrl("qrc:/Constants.qml"), "singleton", 1, 0, "Consts");

Constants.qml is same as you used

pragma Singleton

import QtQuick 2.0

QtObject {
    readonly property string click: 'Mouse Click'
    readonly property string pressHold: 'Mouse PressHold'
}

and then as below example

     MouseArea {
        anchors.fill: parent

        onClicked: {
            console.log("Inside QML Mouse Click")
            TS.printQmlString(Consts.click)
        }

        onPressAndHold: {
            console.log("Inside QML Mouse Press&Hold")
            TS.printQmlString(Consts.pressHold)
        }
    }

Output :

Hope this helps :)
All the best.

sush123

@Pradeep-P-N

Thanks alot i registered using wrong type,

qmlRegisterSingletonType(QUrl("qrc:/Constants.qml"), "singleton", 1, 0, "Consts"); helped me

Pradeep P N

@sush123
You are welcome.

All the best.