need help with objc_util

[SteppenwolfUA]

Hello, everyone

I've started dabbling with objc_util module by trying out sample code provided with Pythonista and reading iOS docs. I find the whole idea of using Objective C from Python exciting. I've managed to set a property like backgroundColor on ui.View. What's struck me is the long time it takes. Almost 3x as long as for normal ui.View. Besides, first I get the default 'vanilla' view and then it gets colored. Any ideas what I am missing here?

from objc_util import *
import ui
import time


# WORKS THE SAME WAY as in Myclass below
#cl = UIColor.alloc()
#cl = cl.init().initWithRed_green_blue_alpha_(.2, .3, .6, 1.).autorelease()


class Myclass (ui.View):
	def __init__(self):
		#ui.View.__init__(self) #changes nothing
		ocv = ObjCInstance(self._objc_ptr)
		cl = UIColor.blueColor()
		ocv.backgroundColor = cl

start = time.clock()
v = Myclass()
v.present('sheet')
print time.clock()-start

start = time.clock()
v2 = ui.View()
v2.background_color('blue')
v2.present('sheet')
print time.clock()-start

Thanx in advance.

[omz]

When you interact with UIKit via objc_util, you have to call most methods on the main UI thread. Otherwise, you'll see strange behavior (e.g. long delays or crashes). objc_util provides the handy on_main_thread decorator for this purpose:

from objc_util import *

class Myclass (ui.View):
    @on_main_thread
    def __init__(self):
        ocv = ObjCInstance(self) #note: _objc_ptr isn't necessary.
        cl = UIColor.blueColor()
        ocv.backgroundColor = cl
# ...

[SteppenwolfUA]

Thank you, Ole! It worked like charm, which again proves the point that reading the docs isn't enough. You need hands-on experience. I was too dumb to put 2 and 2 together despite having read about the

@on_main_thread

decorator.

Your remark about redundant _objc_ptr was an eye-opener. I'm upset 'cause I spent quite some time to dig it out )))) Thanks again.