如何从 C++ 修改 QML 文本

Question

我是 Qt 新手，我正在尝试从 C++ 代码修改 QML 文本（显示在屏幕中）。 我修改了文本，但屏幕上没有更新它，因此我修改了文本变量，但修改了屏幕上的第一个文本。

这是代码：

//main.cpp

#include <QApplication>
#include <QDeclarativeEngine>
#include <QDeclarativeComponent>
#include <QDeclarativeItem>
#include <QDebug>
#include "qmlapplicationviewer.h"

Q_DECL_EXPORT int main(int argc, char *argv[])
{
    QScopedPointer<QApplication> app(createApplication(argc, argv));

    QmlApplicationViewer viewer;
    viewer.setOrientation(QmlApplicationViewer::ScreenOrientationAuto);
    viewer.setMainQmlFile(QLatin1String("qml/textModification/main.qml"));
    viewer.showExpanded();

    QDeclarativeEngine engine;
    QDeclarativeComponent component(&engine, QUrl::fromLocalFile("qml/textModification/main.qml"));
    QObject *object = component.create();

    QObject *item = qobject_cast<QDeclarativeItem*>(object);
    QObject *text = item->findChild<QObject*>("text1");
    qDebug() << "Text of 'text1' when it's created' -------->" << text->property("text");

    text->setProperty("text", "THIS WORKS!");

    qDebug() << "Text of 'text1' after modifying it -------->" << text->property("text");

    return app->exec();
}

//main.qml

import QtQuick 1.0

Item {
    id: item1
    objectName: "item1"
    width: 400
    height: 400

    Text {

        id: text1
        objectName: "text1"
        x: 0
        y: 0
        width: 400
        height: 29
        text: "This text should change..."
        font.pixelSize: 12
    }

}

有人可以帮助我吗？

Answer 1

这可能不像使用 objectName 属性查找对象那么灵活，但这很简单。

main.cpp

#include <QtGui/QApplication>
#include "qmlapplicationviewer.h"
#include <QGraphicsObject>


int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    QmlApplicationViewer viewer;
    viewer.setOrientation(QmlApplicationViewer::ScreenOrientationAuto);
    viewer.setMainQmlFile(QLatin1String("qml/TextTest/main.qml"));
    QObject *rootObject = viewer.rootObject();
    rootObject->setProperty("text1Text",QVariant("Change you text here..."));

    viewer.showExpanded();
    int returnVal = app.exec();
    delete rootObject;
    return returnVal;
}

main.qml

import QtQuick 1.0

Item {
    id: item1
    width: 400
    height: 400
    property alias text1Text: text1.text

    Text {
        id: text1
        width: 400
        height: 29
        color: "red"
        text: "This text should change..."
        font.pixelSize: 12
    }

}