How to intercept any UIApplication openURL calls?

Question

I am using the WeChat SDK to share some of my app's content to WeChat. From my observation, the sharing feature launches the WeChat app with UIApplication openURL. A corner case that the WeChat developers did not handle was to show a warning when the WeChat app is not installed at all. I want to handle this case myself by first checking canOpenUrl with the same URL passed into openURL. Unfortunately, I do not know the WeChat URL scheme because I only have their header and compiled files. Is there any way to intercept any openURL calls to figure out what URL is being opened?

Answer 1

Subclass UIApplication and have the app use your subclass. In your subclass, override openURL: and add your logic. When you're happy to continue with the open operation, call [super openURL:...];.

Teach the app to use your custom subclass by editing the main.m file:

return UIApplicationMain(argc, argv, NSStringFromClass([XXApplication class]), NSStringFromClass([XXAppDelegate class])); 

(Assuming XXApplication is your app subclass and XXAppDelegate is your app delegate class, and remembering to import the appropriate headers)