QJsonArray 传给QML后不能用.length等问题



  • 如题,QJsonArray传给qml后,[]、length等方法不能获取数据里面的值,请问大神,在qml里面如何使用传过来的QJsonArray数组(获取其中的值)


  • 网站研运

    @fish 看看typeof,一般都会变成object。如果不巧是ListModel,那么可以使用count来代替Length



  • @fish 有没有具体的代码?



  • @fish

    先说结果,就是 QJsonArray 在 qml 中可以使用 [] 进行随机访问,也可以用 length

    测试文件如下:sample.hpp

    #include <QJsonArray>
    #include <QJsonValue>
    #include <QJsonObject>
    
    class SampleTest : public QObject
    {
        Q_OBJECT
    public:
        SampleTest(QObject* parent = nullptr):
            QObject(parent)
        { }
    
        Q_INVOKABLE QJsonArray getJsonArray() const {
             QJsonArray array;
             array.append(QJsonValue("string"));
             array.append(QJsonValue("string"));
             return array;
        }
    
       Q_INVOKABLE QJsonValue getJsonValue() const {
            QJsonArray array;
            array.append(QJsonValue("string"));
            array.append(QJsonValue("string"));
            return array;
        }
    
    };
    

    main.cpp

    #include <QApplication>
    #include <QQmlApplicationEngine>
    #include <QtQml>
    
    #include "sample.hpp"
    
    int main(int argc, char *argv[])
    {
        QApplication app(argc, argv);
    
        QQmlApplicationEngine engine;
    
        engine.load(QUrl(QStringLiteral("qrc:/qml/main.qml")));
    
        engine.rootContext()->setContextProperty("CppArray", new SampleTest(&engine));
    
        return app.exec();
    }
    

    main.qml

    import QtQuick 2.5
    import QtQuick.Controls 1.4
    import QtQuick.Layouts 1.1
    
    
    ApplicationWindow {
        visible: true
        width: 640
        height: 480
        title: qsTr("QML Cpp Array")
    
        Button {
            text: "clicked"
            onClicked: {
                var jsonArray = CppArray.getJsonArray();
                var jsonValue = CppArray.getJsonValue();
                console.log(jsonArray.length, jsonArray[0])
                console.log(jsonValue.length, jsonValue[0])
            }
        }
    }
    

    控制台打印:

    qml: 2 string
    qml: 2 string
    

    所以你的代码要仔细审阅。


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