How can I present a UIAlertController?

[ProfSpaceCadet]

I am working on a Pythonista script that displays a UITabBarController, which contains multiple UINavigationControllers, containing UITableViewControllers. At some point I need to display a UIAlertController, but all the methods I've tried to present it either crash the app or push the UIAlertController to the navigation stack.

My code:

from objc_util import *
from UIKit import *
    
alert = UIAlertController.alertControllerWithTitle_message_preferredStyle_('Title', 'Message', 0)
def alertActionCancel(sender):
  print 'Cancelled!'
alertActionCancelBlock = ObjCBlock(alertActionCancel, None, [c_void_p])
retain_global(alertActionCancelBlock)
alert.addAction_(UIAlertAction.actionWithTitle_style_handler_('Cancel', 1, alertActionCancelBlock))
myTableViewController.presentViewController_animated_completion_(alert, True, None) # This line crashes Pythonista

Thanks in advance, any help is greatly appreciated.

[blmacbeth]

I know this! I made a post a while back when I was experimenting with objc_util. The basic idea is to get the SUIViewController (a special Pythonista subclass of UIViewController) and use that to present the alert. Things tend to crash otherwise…

Here is a link to my post, which has snippets of code that can get you started.

B

https://forum.omz-software.com/topic/2314/share-code-uialertcontroller

[ProfSpaceCadet]

I have tried using SUIViewConrroller, but Pythonista still crashes. viewControllerForView_ seems to just return my original view controller.

P.S. This seems to be more of a issue on iPad.

[blmacbeth]

That's weird. I wrote and tested the script on my iPad. Did you run the exact script in the linked post? Should be the second script that doesn't crash.

Here is the code, if you don't care to guess.

B.

# coding: utf-8
from objc_util import *
import ctypes
import ui

SUIViewController = ObjCClass('SUIViewController')
UIAlertController = ObjCClass('UIAlertController')
UIAlertAction     = ObjCClass('UIAlertAction')

def ok_pressed(sender):
    print 'OK pressed', ObjCInstance(sender), dir(ObjCInstance(sender))

alert = UIAlertController.alertControllerWithTitle_message_preferredStyle_(ns('My Alert'), ns('My Message'), 0)
alert_action_block = ObjCBlock(ok_pressed, None, [c_void_p])
default_action = UIAlertAction.actionWithTitle_style_handler_(ns('OK'), 0, alert_action_block)
alert.addAction_(default_action)
##rvc.presentModalViewController_animated_(alert, True)

## Stop Crashes
retain_global(alert_action_block)

def button_tapped(sender):
    super_view = sender.superview
    super_view_pntr = ObjCInstance(super_view)
    vc = SUIViewController.viewControllerForView_(super_view_pntr)
    vc.presentModalViewController_animated_(alert, True)
    
view = ui.View(frame=(0,0,500,500))
view.name = 'Demo'
view.background_color = 'white'
button = ui.Button(title='Tap me!')
button.center = (view.width * 0.5, view.height * 0.5)
button.flex = 'LRTB'
button.action = button_tapped
view.add_subview(button)
view.present('sheet')