Super slow lag/delay on initial keyboard animation of UITextField

Question

Before you implement any exotic hacks to get around this problem, try this: stop the debug session, close the app from multitasking, unplug your device from the computer and run the app normally by tapping its icon. I have seen at least two cases in which the delay only occurs while the device is plugged in.

So the problem is NOT just limited to the first install as I had previously thought, but happens every time the app is launched. Here's my solution that solves the issue completely.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  // Preloads keyboard so there's no lag on initial keyboard appearance.
  UITextField *lagFreeField = [[UITextField alloc] init];
  [self.window addSubview:lagFreeField];
  [lagFreeField becomeFirstResponder];
  [lagFreeField resignFirstResponder];
  [lagFreeField removeFromSuperview];
}

Yeah, I also got a few seconds delay on the latest iPhone 4s. Don't panic. For some reasons, it only happens the first time the app is loaded from Xcode in Debug. When I did Release, I don't get the delay. Just forget it...

This is a known issue.

Preloading keyboard seems promising. Check Preloading the UIKeyboard.

Some additional reading material:

Initial iPhone virtual keyboard display is slow for a UITextField. Is this hack around required?

UITextField keyboard blocks runloop while loading?

http://www.iphonedevsdk.com/forum/iphone-sdk-development/12114-uitextfield-loooong-delay-when-first-tapped.html

You can use Vadoff's solution in Swift by adding this to didFinishLaunchingWithOptions:

// Preloads keyboard so there's no lag on initial keyboard appearance.
let lagFreeField: UITextField = UITextField()
self.window?.addSubview(lagFreeField)
lagFreeField.becomeFirstResponder()
lagFreeField.resignFirstResponder()
lagFreeField.removeFromSuperview()

It is working for me in iOS 8.

Code in block added to main queue and run asynchronously. (don't locked main thread)

dispatch_async(dispatch_get_main_queue(), ^(void){
      [textField becomeFirstResponder];
 });