change CustomViewController fields from AppDelegate - ios

Question

I'm new to ios(android dev)
I'm handling opening my app from url, and i got the url in current method in my AppDelegate.
- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url
sourceApplication:(NSString *)sourceApplication annotation:(id)annotation {
NSLog(#"Calling Application Bundle ID: %#", sourceApplication);
NSLog(#"URL scheme:%#", [url scheme]);
NSLog(#"URL query: %#", [url query]);
return YES;
}
There are certain params in my link which i'd like to use to fill the textField of my LoginViewController.
Can i communicate with LoginViewController from AppDelegate? consider that LoginViewController already didLoad.

Answer 1

You can define one property let’s say strName in appDelegate.
Then you have to assign it’s value from this method
- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url
sourceApplication:(NSString *)sourceApplication annotation:(id)annotation {
NSLog(#"Calling Application Bundle ID: %#", sourceApplication);
NSLog(#"URL scheme:%#", [url scheme]);
NSLog(#"URL query: %#", [url query]);
//for example
self.strName = [url query];
return YES;
}
Now you can access this property from anywhere.
Create Instance of appDelegate In your viewController
#define AppDel ((AppDelegate *)[UIApplication sharedApplication].delegate)
Then assign as below
textfield.text = AppDel.strName;

Answer 2

You can communicate with your controller in several ways:
Hold instance in appDelegate and call methods.
Save your data in some sort of storage (UserDefault for ex.) and extract in in viewWillAppear or viewDidAppear methods.
Use your own observer pattern implementation or NotificationCenter