Javascript 将回调作为参数发送到QJSValue::callAsConstructor()
当尝试使用QJSEngine从C++调用JavaScript函数时,其值存储函数的所有参数属性都会神秘地丢失。为什么会这样?有没有办法解决这个问题?如果您试图传递一个没有对象的函数,那么未定义的值也会被传输 qjsengine bugJavascript 将回调作为参数发送到QJSValue::callAsConstructor(),javascript,c++,qt,qml,qt5,Javascript,C++,Qt,Qml,Qt5,当尝试使用QJSEngine从C++调用JavaScript函数时,其值存储函数的所有参数属性都会神秘地丢失。为什么会这样?有没有办法解决这个问题?如果您试图传递一个没有对象的函数,那么未定义的值也会被传输 qjsengine bug QT += core qml quick quickcontrols2 TARGET = qjsengine-bug TEMPLATE = app DEFINES += QT_DEPRECATED_WARNINGS CONFIG += c++11 console
QT += core qml quick quickcontrols2
TARGET = qjsengine-bug
TEMPLATE = app
DEFINES += QT_DEPRECATED_WARNINGS
CONFIG += c++11 console
SOURCES += main.cpp
main.cpp
#include <QCoreApplication>
#include <QJSValueIterator>
#include <QJSEngine>
#include <QJSValue>
#include <QtGlobal>
#include <iostream>
void myMessageOutput(
QtMsgType t,
const QMessageLogContext &c,
const QString &msg
) {
Q_UNUSED(t);
Q_UNUSED(c);
std::cout << msg.toStdString() << "\n";
}
int main(int argc, char *argv[]) {
qInstallMessageHandler(myMessageOutput);
QCoreApplication app(argc, argv);
QJSEngine engine;
engine.installExtensions(QJSEngine::ConsoleExtension);
QJSValue constructor = engine.evaluate(
"(function Component(props){console.log(JSON.stringify(props))})"
);
QJSValue callBack = engine.evaluate("(function(text){console.log(text)})");
callBack.call({"There is no error. Valid JavaScript code..."});
callBack.call({"Let's create an object, add a couple of props to it"});
QJSValue object = engine.newObject();
object.setProperty("First", 1);
object.setProperty("Second", callBack);
object.setProperty("Third", "#2");
QJSValueIterator iter(object);
while (iter.hasNext()) {
iter.next();
callBack.call({
QString("name: %1, value: %2")
.arg(iter.name())
.arg(iter.value().toString())
});
}
callBack.call({"Correct. Three fields"});
callBack.call({"Let's try to pass an object to the constructor parameters"});
constructor.callAsConstructor({object});
callBack.call({"Where did the second property go?"});
return app.exec();
}
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无效myMessageOutput(
QtMsgType t,
常量QMessageLogContext&c,
常量QString和msg
) {
Q_(t);
Q_(c);
std::cout根据定义,没有任何东西来表示函数,因此JSON.stringify
函数作为属性将导致“缺少”属性(或数组中的函数或函数)