How can I change some keystroke on iOS 7 default keyboard? Like Slack

Question

I use an app called "Slack" somehow they managed to change the return key to be "#" and "@" like in the picture.

I really don't know whether they created a whole new keyboard view that look exactly the same as iOS default keyboard or

It has a way to custom the return button of the default keyboard.

Anyone got any idea how can they do this on iOS 7?

Slack has shared it source code for handle message like app here

Which I still cannot locate where is the functionality to add "@" and "#"

Answer 1

You can achieve this by using the Twitter keyboard built in to the iOS SDK.

[textField setKeyboardType:UIKeyboardTypeTwitter];

If you're using Interface Builder, select your UITextField and go to the Attributes inspector -> Keyboard Type -> Twitter.