Presenting ViewController

filippocld

Ok, i was trying to do this without any help but i'm stuck.
I basically have this code

from objc_util import *
from time import sleep
#import objutil

ObjCClass('NSBundle').bundleWithPath_('/System/Library/Frameworks/ReplayKit.framework').load()

recorder=ObjCClass('RPScreenRecorder')
preview=ObjCClass('RPPreviewViewController')
sharedrecorder=recorder.sharedRecorder()
sharedrecorder.startRecordingWithMicrophoneEnabled_handler_(False,None)#(false,none)

print 'Recording:' + str(sharedrecorder.isRecording())
print 'Microphone Enabled:' + str(sharedrecorder.isMicrophoneEnabled())
sleep(3)
#Some cool things...

#Stopping the recording and saving
print 'Stopping...'
sharedrecorder.stopRecordingWithHandler_(preview)
app = ObjCClass('UIApplication').sharedApplication()
rootvc=app.keyWindow().rootViewController()
rootvc.presentViewController_animated_completion_(preview, True, None)

That "implements" a iOS 9 API (ReplayKit) and records the screen for a certain time (3 secs in this case) and then it has to present the preview view controller. But the app crashes.

Can someone help me (again)?
Thanks in advance
Filippo

omz

The problem is, you pass a view controller class to stopRecordingWithHandler_, but it expects a block... With the current beta, it's pretty difficult to make this work at all (blocks aren't really supported), but I can show you an example when the new build is up on TestFlight (probably later today). As it happens, I've been experimenting with exactly this API as well...

filippocld

Thanks, waiting for it :-)

omz

Okay, here's a minimal example that shows how you can use RPScreenRecorder – as I said, it'll only work with the latest build (#160023), so please install that first.

Note to others who might be reading this: You also need to have the iOS 9 beta installed for this to work.

from objc_util import *
import time

NSBundle = ObjCClass('NSBundle')
replaykit = NSBundle.bundleWithPath_('/System/Library/Frameworks/ReplayKit.framework')
replaykit.load()

RPScreenRecorder = ObjCClass('RPScreenRecorder')

def stop_callback(_cmd, _vc):
	vc = ObjCInstance(_vc)
	rootvc = UIApplication.sharedApplication().keyWindow().rootViewController()
	vc.popoverPresentationController().setSourceView_(rootvc.view())
	rootvc.presentViewController_animated_completion_(vc, True, None)

stop_handler = ObjCBlock(stop_callback, restype=None, argtypes=[c_void_p, c_void_p])

recorder = RPScreenRecorder.sharedRecorder()

@on_main_thread
def start_recording():
	recorder.startRecordingWithMicrophoneEnabled_handler_(False, None)

@on_main_thread
def stop_recording():
	recorder.stopRecordingWithHandler_(stop_handler)

start_recording()
time.sleep(5)
stop_recording()

filippocld

Thanks.
What is @on_main_thread for?

omz

What is @on_main_thread for?

I think it's not strictly necessary here, but most things that have to do with UI need to be called from the main thread.

filippocld

It crashes :-( i copied exactly what you wrote and crashes 😱

omz

Hmm. What kind of device do you have? Could be that it doesn't work on 32 bit...

filippocld

Ipad air 2, it is 64 bit. I noticed removing on main thread crashes the app after the recording and before the presentation, leaving it crashes when start_recording() is called

omz

Okay, no idea what might be causing the crash then, sorry. :/

It doesn't crash here at all, but I've noticed that the resulting videos contain strange artifacts (looks like tearing), not sure if that's related somehow.

filippocld

Ok, will try to solve it by me :-/
If you find something that could cause crashes tell me

filippocld

I'm near to the solution.
I removed @on_main_thread (that crashes many scripts i already worked on and worked with previous beta) and i tried to experiment with ObjCBlocks, always with a crash. So downloaded the example in the docs about the blocks. Guess what? It Crashes! The crash definitely has to do with blocks

Hope this helps solving the bug,
Filippo

omz

I'll do some more testing. It might have to do with different build settings in the TestFlight version vs. my local development build – after all, the code I posted definitely works here, and I don't think hardware differences are responsible for this (iPad Air 1 vs. 2 aren't that different).

I think this particular use case is possible to do without blocks (using a delegate instead), but it would still be nice if I could get those to work reliably.

filippocld

Thanks :-)
Did some (more and more) testing with the example file and found that maybe the line 14 (where the handler is called) is responsible for the crash

ywangd

I can run the example block code (sorting function) from the documentation. My device is also a iPad Air 2.

The RPScreenRecorder did NOT run but it was due to a different error. The replaykit was not created successfully. The bundleWithPath_ method returned a None for me.

filippocld

Your error is there because you have iOS 8. ReplayKit is a framework of iOS 9.

Dunno about the example, maybe is some iOS 9 bug

@omz I was wrong, the line that crashes the app is line 14, where you call the handler. Anyway @on_main_thread crashes too for me. Remember i am on iPad Air 2 WiFi iOS 9 beta 5

filippocld

Ok, @omz in the meantime can you show me how to do with delegates, please? :-)
Would be much appreciated

omz

@filippocld said:

Ok, @omz in the meantime can you show me how to do with delegates, please? :-)
Would be much appreciated

Turns out that I was wrong about that. It's not possible to do this without blocks.

I don't really have any idea why this doesn't work for you, to be honest. I installed the latest beta directly from TestFlight (the exact same build you have) on an iPad Air 1 that has iOS 9 beta 5 installed, and it works just fine. I just can't think of a reason why it wouldn't work on an iPad Air 2 right now.

filippocld

Do you have a way to see my crash logs and maybe understand the problem?
I mean, it happens everytime i call an handler in every function, it shouldn't be so difficult.

omz

I only get aggregate crash reports, and they're delayed, so if you could send me one of yours, that might be helpful (Settings app → privacy → diagnostics & usage → diagnostics & usage data). I can't really promise that I can fix this though – as I've mentioned in the docs, the whole ObjCBlock feature is extremely experimental and relies on stuff that isn't really documented anywhere.