[Interest] Qt/iOS subclassing and/or delegating
Ben Lau
xbenlau at gmail.com
Fri May 29 15:33:52 CEST 2015
You may override existing method just like what I did to openUrl and
didFinishLaunchingWithOptions
on QIOSApplicationDelegate even you don't have the header file.
On 29 May 2015 at 21:25, maitai <maitai at virtual-winds.org> wrote:
> I tried but didn't succeed. If I understand well (which is far from
> being certain), I can only add new methods or properties that way, not
> override existing ones unless a protocol is defined that would allow me to
> create a delegate on QIOViewController, but there is no as far as I can see.
>
> I might be wrong, though. I even hope so.
>
>
>
>
> Le 29-05-2015 15:18, Ben Lau a écrit :
>
>
> Why don't use categories that suggested by people here?
>
>
> On 29 May 2015 at 21:11, maitai <maitai at virtual-winds.org> wrote:
>
>> Finally got it working... with a bad hack
>>
>> I cloned QIOSViewController.h and .mm from qt sources (and added qt's
>> iOS headers in my include path, I already had core-private and
>> gui-private in my pro files) and modified it to do what I want. I also
>> had to add a lockedOrientation property to it for some mysterious
>> reason...
>>
>> At least it's doing what I need (i.e. ignore device rotation when I
>> decide to). Of course it's a really bad hack and I'm still hoping
>> someone can point me to a better solution.
>>
>> Thanks
>> Philippe.
>>
>>
>> Le 29-05-2015 11:24, maitai a écrit :
>> > I had a look at QT sources... Basically what I want to do is override
>> > QIOSViewController:shouldAutorotate.
>> >
>> > I tried
>> > @interface MyIOSViewController : QIOSViewController
>> > @end
>> > @implementation MyIOSViewController
>> > - (BOOL) shouldAutorotate {
>> > NSLog(@"Inside shouldAutorotate");
>> > return NO;
>> > }
>> >
>> > It compiles and does not crash (I import QIOSViewController.h), but
>> > that
>> > all it does...
>> >
>> >
>> > Le 29-05-2015 10:23, Harri Pasanen a écrit :
>> >> Compared to C++, Objective-C is very dynamic language and you can do
>> >> many things at runtime.
>> >>
>> >> So you can add methods to existing classes using categories:
>> >>
>> https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/ProgrammingWithObjectiveC/CustomizingExistingClasses/CustomizingExistingClasses.html
>> >>
>> >> Or resort to something quite funky to replace existing methods:
>> >> https://github.com/rentzsch/jrswizzle
>> >>
>> >> As to your original question, rotation handling is surprisingly tricky
>> >> even in pure Objective-C if you want to conditionally rotate. For
>> >> instance iOS 8.3 broke some of my code handling that which had worked
>> >> fine since iOS 6, pure Objective-C.
>> >>
>> >> I don't know how Qt hooks into it.
>> >>
>> >> Harri
>> >>
>> >> On 29/05/2015 09:41, Robert Iakobashvili wrote:
>> >>> On Fri, May 29, 2015 at 8:38 AM, maitai <maitai at virtual-winds.org>
>> >>> wrote:
>> >>>> Thanks Ben for your reply
>> >>>>
>> >>>> After much digging I made some progress but I am still looking for a
>> >>>> way to
>> >>>> temporary lock screen auto rotation.
>> >>>>
>> >>>> I have created my own app delegate to catch openUrl(), and
>> >>>> surprisingly it
>> >>>> works. I register my app delegate from main.cpp by calling something
>> >>>> like
>> >>>> this:
>> >>>>
>> >>>> void QtAppDelegateInitialize ()
>> >>>>
>> >>>> {
>> >>>>
>> >>>> QtAppDelegate *appDelegate = (QtAppDelegate *)[[UIApplication
>> >>>> sharedApplication] delegate];
>> >>>>
>> >>>> [[UIApplication sharedApplication] setDelegate:[QtAppDelegate
>> >>>> sharedQtAppDelegate]];
>> >>>>
>> >>>> NSLog(@"Created a new appdelegate");
>> >>>>
>> >>>> }
>> >>>>
>> >>>>
>> >>>>
>> >>>> I then found this very interesting post:
>> >>>>
>> https://forum.qt.io/topic/48745/how-to-get-didfinishlaunchingwithoptions-called-in-ios-delegate/7
>> >>>> which links to this bug report: QTBUG-38184.
>> >>>>
>> >>>> First question: I am now wondering how my delegate can possibly work
>> >>>> since
>> >>>> it seems I can have only one delegate... so what happened to
>> >>>> QIOSApplicationDelegate?
>> >>>>
>> >>>> I then tried various things to add yet another delegate this time
>> >>>> based on
>> >>>> UINavigationControllerDelegate, but although after much sweat it
>> >>>> seems to
>> >>>> load, the various methods I am trying to override are never called
>> >>>> when I
>> >>>> rotate the device.
>> >>>>
>> >>>> Could it be that I should instead modify/interface
>> >>>> QIOSApplicationDelegate
>> >>>> itself and not try to create my own delegates?
>> >>>>
>> >>>> A bit confused at this point, I admit ;)
>> >>>>
>> >>>> Thanks for any tip
>> >>>>
>> >>>> Philippe Lelong
>> >>>>
>> >>>>
>> >>>>
>> >>>> Le 27-05-2015 20:24, Ben Lau a écrit :
>> >>>>
>> >>>>
>> >>>>
>> >>>> On 28 May 2015 at 02:07, maitai <maitai at virtual-winds.org> wrote:
>> >>>>> Hello all,
>> >>>>>
>> >>>>> I've started to port on iOS and need to override some methods, like
>> >>>>> we
>> >>>>> do easily through Java on Qt/Android. I succeeded to implement an
>> >>>>> appDelegate in objective-C that works for some events like openURL
>> >>>>> and
>> >>>>> such, but for instance I also need to lock automatic screen
>> >>>>> rotation
>> >>>>> in
>> >>>>> some circumstances (but not always).
>> >>>>
>> >>>> Objective-C has a feature to replace the original method of a class.
>> >>>> So you
>> >>>> may just override the method you needed (In case it don't break Qt)
>> >>>> Customizing Existing Classes
>> >>>>
>> >>>> Example Code:
>> >>>> quickios/appdelegate.mm at 0b067e17dc13b8533ca3f7dd574d7e81ea17a015
>> >>>> ·
>> >>>> benlau/quickios
>> >>>>
>> >>>> I have tested to override openURL and didFinishLaunchingWithOptions
>> >>>> of
>> >>>> AppDelegate with Qt 5.4.1. This method works.
>> >>>>
>> >>>>> I read that I should somehow override "bool
>> >>>>> UINavigationController::shouldRotate()"
>> >>>>
>> >>>> Never tried. But should be worth to try? I am also be interested
>> >>>> with
>> >>>> your
>> >>>> result.
>> >>>>
>> >>>>> Should I reimp (subclass?) UINavigationController and how? Or is
>> >>>>> there a
>> >>>>> way to create a new delegate or even better to extend my current
>> >>>>> appDelegate?
>> >>>>>
>> >>>>>
>> >>>>> I'm new to Objective-C as you can guess... Any clue would be really
>> >>>>> appreciated :)
>> >>>>>
>> >>>>> Thanks
>> >>>>> Philippe Lelong
>> >>> Dear Philippe,
>> >>>
>> >>> Please see the reply Tor Arne inside
>> >>>
>> >>> https://bugreports.qt.io/browse/QTBUG-42123
>> >>>
>> >>> That could be an answer - Let it be.
>> >>>
>> >>> Sincerely,
>> >>> Robert
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