Passing a QObject to an Script function with QJSEngine? - qt

Question

I'm trying to call a function in an external script while passing a QObject as a parameter.
My QObject is defined as this:
#ifndef INSERTVALUES_H
#define INSERTVALUES_H
#include <QObject>
struct insertValueDef
{
QString name;
QString xmlCode;
QString value;
bool key;
bool insert;
};
typedef insertValueDef TinsertValueDef;
class insertValues : public QObject
{
Q_OBJECT
public:
explicit insertValues(QObject *parent = 0);
~insertValues();
void insertValue(TinsertValueDef value);
int count();
void setItemName(int index, QString name);
void setItemXMLCode(int index, QString xmlCode);
void setItemValue(int index, QString value);
void setItemIsKey(int index, bool isKey);
void setItemToInsert(int index, bool toInsert);
QString itemName(int index);
QString itemXMLCode(int index);
QString itemValue(int index);
bool itemIsKey(int index);
bool itemToInsert(int index);
bool valueIsNumber(int index);
int getIndexByColumnName(QString name);
private:
QList<TinsertValueDef> m_insertList;
};
#endif // INSERTVALUES_H
My JS Script function is this:
function beforeInsert(table,data)
{
if (table == "tmpTable")
{
var index = data.getIndexByColumnName("tmpfield");
if (index >= 0)
{
data.setItemValue(index,"Carlos Quiros");
}
}
}
The code that runs runs the script is the following:
QFile scriptFile(javaScript);
if (!scriptFile.open(QIODevice::ReadOnly))
{
log("Error: Script file defined but cannot be opened");
return 1;
}
JSEngine.evaluate(scriptFile.readAll(), javaScript);
scriptFile.close();
insertValues insertObject;
TinsertValueDef tfield;
tfield.key = false;
tfield.name = "tmpfield";
tfield.xmlCode = "tmpCode";
tfield.value = "tmpValue";
tfield.insert = true;
insertObject.insertValue(tfield);
QString error;
beforeInsertFunction = JSEngine.evaluate("beforeInsert",error);
if (!beforeInsertFunction.isError())
{
QJSValue insertListObj = JSEngine.newQObject(&insertObject);
QJSValue result = beforeInsertFunction.call(QJSValueList() << "tmpTable" << insertListObj);
if (result.isError())
{
log("Error calling BeforInsert JS function.");
return 1;
}
else
{
log("JS function seems to be ok");
for (int pos = 0; pos < insertObject.count(); pos++)
{
log(insertObject.itemName(pos) + "-" + insertObject.itemValue(pos));
}
return 1;
}
}
else
{
log("Error evaluating BeforInsert JS function. [" + error + "]");
return 1;
}
I can see that the parameter "table" is passing properly but the rest of the code is not working. I guess I cannot do:
var index = data.getIndexByColumnName("tmpfield");
Any idea what am I doing wrong? and what else should I do to make it work?
Thanks,

Answer 1

In order to access properties or invoke methods of QObjects passed to QJSEngine (or to QML), you need to declare them using Q_PROPERTY and Q_INVOKABLE macros in your QObject-derived class declaration.
Please see the Qt documentation for more details: Exposing Attributes of C++ Types to QML