[Interest] Qt/iOS subclassing and/or delegating

Fri May 29 15:43:05 CEST 2015

I think you can do that because openUrl is the only method implemented
in the original QIOApplicationDelegate. So in fact you added
didFinishLaunchingWithOptions and replaced openUrl. But if there were
other methods (and QIOViewController has many), you would have been
obliged to duplicate them all, at least that's what I understand. Am I
wrong? 

Le 29-05-2015 15:33, Ben Lau a écrit : 

> 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 [1]
>>>
>>> Or resort to something quite funky to replace existing methods:
>>> https://github.com/rentzsch/jrswizzle [2]
>>>
>>> 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 [3]
>>>>> 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 [4]: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 [5] 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 [6]
>>>>
>>>> That could be an answer - Let it be.
>>>>
>>>> Sincerely,
>>>> Robert
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Links:
------
[1]
https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/ProgrammingWithObjectiveC/CustomizingExistingClasses/CustomizingExistingClasses.html
[2] https://github.com/rentzsch/jrswizzle
[3]
https://forum.qt.io/topic/48745/how-to-get-didfinishlaunchingwithoptions-called-in-ios-delegate/7
[4] tel:27-05-2015%2020
[5] http://appdelegate.mm
[6] https://bugreports.qt.io/browse/QTBUG-42123
[7] http://lists.qt-project.org/mailman/listinfo/interest
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