Hi
I'm sorry for the burst of emails, and I'm not sure if this should be a
new thread or not.
Another issue we are having with qmllint is adding type information for
objects added to the global object in C++. We've used this to provide
custom log and assert functions, but obviously the linter doesn't know
about them. If they are added to qml/jsroot.qmltypes (along similar
lines to the 'Console' type) then the linter does know about the type.
Is there a way to register types in the global property 'externally' ?
I've tried a few variations of using the '-i' option in the linter, but
without success.
Many thanks
Matthew Fincham
On 2023/08/30 15:24, Matthew Fincham via Interest wrote:
Hi Ulf
Thank you for your response.
-- QtLocation --
Thanks for catching this. See
https://codereview.qt-project.org/c/qt/qtlocation/+/500504 for a fix.
That's great, thank you.
-- 'as' operator --
This should work. Type assertions (aka "as cast") are documented in
https://doc.qt.io/qt-6/qtqml-javascript-hostenvironment.html . What
kind of object does the loader produce here? Can you please open a
bug report with a minimal example?
A bug report has been added: https://bugreports.qt.io/browse/QTBUG-116614
-- Enums in gadgets --
So, what you want to do is expose MyType as a namespace instead:
namespace MyTypeNamespace {
Q_NAMESPACE
QML_FOREIGN_NAMESPACE(MyType)
QML_NAMED_ELEMENT(MyType)
}
You cannot have reference semantics on a value type. A type with
reference semantics (aka an "object type") needs to be derived from
QObject and have a Q_OBJECT macro. The engine plays somewhat loose
with that and allows you to still access enums from such broken
types. We should amend the documentation to warn about this problem
and also generate a run time warning from the engine.
The example gadget was not the best. The gadget is used as an actual
value type in qml. A fuller example (as I have it) would be:
C++:
struct TestGadget
{
Q_GADGET
QML_ELEMENT
Q_PROPERTY(int value MEMBER value)
public:
enum class GadgetEnum
{
OptionA,
OptionB,
OptionC,
};
Q_ENUM(GadgetEnum)
public:
static void registerType();
public:
int value = 0;
};
QML: (apart from where it is used as a data type) example usage would be
// reference an instance of the gadget
... someGadgetValue.value ...
// use the enum
console.log(TestGadget.GadgetEnum.OptionB)
I've tried various permutations of the namespace macros you described,
but can't get it right. Firstly, is this possible, and if it is, what
is the canonical way of doing this? As it is it works, but you have
said it is actually a broken type.
As a side note - a Google search for "qml q_gadget enum" has these as
the top two results (at least for me) which both recommend something
along the lines of the above.
-
https://stackoverflow.com/questions/66855134/how-to-access-a-q-enum-declared-in-c-class-from-qml
- https://qml.guide/enums-in-qt-qml
I know they are not Qt documentation. Just pointing it out - it would
be nice if the Qt could somehow get a canonical example to the top of
that search.
Thanks again for the feedback
Kind regards
Matthew
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