Qt-interest Archive, July 2007
QtScript bug calling C++ functions with QVariant arguments
Message 1 in thread
Given these 2 C++ slots within a QObject made available to QtScript:
public Q_SLOTS:
void foo(const QVariant& a1);
void bar(const QVariant& a1, int a2 = 1);
These calls in QtScript will both fail with the message "incorrect number or
type of arguments in call to ...":
obj.foo(1);
obj.bar(1);
However this call will work without error:
obj.bar(1, 1);
Can anybody confirm?
Any workaround of patch available?
Thanks,
Seneca
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Message 2 in thread
Yet another bug where converting from QVariant fails:
The method in C++ QObject:
public Q_SLOTS:
QVariant foo() const { return QVariant(1); }
The QtScript code:
print(obj.foo()); // prints: "undefined" instead of "1"
This leaves QVariant completely unusable as arguments or return values of
C++ methods in the current Qt 4.3.0 release.
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Message 3 in thread
Seneca wrote:
> Yet another bug where converting from QVariant fails:
>
> The method in C++ QObject:
>
> public Q_SLOTS:
> QVariant foo() const { return QVariant(1); }
>
>
> The QtScript code:
>
> print(obj.foo()); // prints: "undefined" instead of "1"
>
>
> This leaves QVariant completely unusable as arguments or return values of
> C++ methods in the current Qt 4.3.0 release.
>
Hi Seneca,
This is fixed for 4.3.1. The work-around for 4.3.0 is to do
Q_DECLARE_METATYPE(QVariant)
and then
qMetaTypeId<QVariant>();
somewhere in your application.
Regards,
Kent
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Message 4 in thread
Thanks very much Kent,
Everything works perfectly now with your workaround!
> This is fixed for 4.3.1. The work-around for 4.3.0 is to do
>
> Q_DECLARE_METATYPE(QVariant)
>
> and then
>
> qMetaTypeId<QVariant>();
>
> somewhere in your application.
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Message 5 in thread
Hi!
> Q_DECLARE_METATYPE(QVariant)
>
> and then
>
> qMetaTypeId<QVariant>();
>
> somewhere in your application.
I had no luck with this... I tried, but for example if I have a String
in a QVariant I will get something like "variant(QString, )" in the
script itself (or I did not understand the concept of QVariant in an
Scripting Envrironment).
Finally I wrote the following function:
QScriptValue workaroundVariant2ScripValue(QScriptEngine *e, QVariant var)
{
switch(var.type())
{
case QVariant::Invalid:
return e->nullValue();
case QVariant::Bool:
return QScriptValue(e, var.toBool());
case QVariant::Date:
return e->newDate(var.toDateTime());
case QVariant::DateTime:
return e->newDate(var.toDateTime());
case QVariant::Double:
return QScriptValue(e, var.toDouble());
case QVariant::Int:
case QVariant::LongLong:
return QScriptValue(e, var.toInt());
case QVariant::String:
return QScriptValue(e, var.toString());
case QVariant::Time:
return e->newDate(var.toDateTime());
case QVariant::UInt:
return QScriptValue(e, var.toUInt());
}
if(var.isNull())
return e->nullValue();
// bad but better then nothing
return QScriptValue(e, var.toString());
}
This works... (for me).
Greetings
Niklas
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Message 6 in thread
>
> QScriptValue workaroundVariant2ScripValue(QScriptEngine *e, QVariant var)
sorry, made a mistake. This one is ok (isNull() check first):
QScriptValue workaroundVariant2ScriptValue(QScriptEngine *e, QVariant var)
{
if(var.isNull())
return e->nullValue();
switch(var.type())
{
case QVariant::Invalid:
return e->nullValue();
case QVariant::Bool:
return QScriptValue(e, var.toBool());
case QVariant::Date:
return e->newDate(var.toDateTime());
case QVariant::DateTime:
return e->newDate(var.toDateTime());
case QVariant::Double:
return QScriptValue(e, var.toDouble());
case QVariant::Int:
case QVariant::LongLong:
return QScriptValue(e, var.toInt());
case QVariant::String:
return QScriptValue(e, var.toString());
case QVariant::Time:
return e->newDate(var.toDateTime());
case QVariant::UInt:
return QScriptValue(e, var.toUInt());
}
// bad but better then nothing
return QScriptValue(e, var.toString());
}
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