An RxSwift subclass of UITextView which allows for observation of taps on an arbitrary portion of text.

InteractiveTextView.swift

//
//  InteractiveTextView.swift
//  Views
//
//  Created by James Valaitis on 05/03/2018.
//  Copyright © 2018 VIPR Digital. All rights reserved.
//

import RxSwift
import UIKit

//  MARK: Interactive Text View
/**
A text view with support for tapping on certain words.
 */
open class InteractiveTextView: UITextView {
	//  MARK: Properties
	private let interactiveAttribute = NSAttributedStringKey("com.fixr.interactiveAttribute")
	private typealias Callback = () -> ()
	private var callbacks = [String: Callback]()
	//  MARK: Initialization
	public override init(frame: CGRect, textContainer: NSTextContainer?) {
		super.init(frame: frame, textContainer: textContainer)
		setup()
	}
	public required init?(coder aDecoder: NSCoder) {
		super.init(coder: aDecoder)
		setup()
	}
}
//  MARK: Configuration
private extension InteractiveTextView {
	func setup() {
		isUserInteractionEnabled = true
		let tapRecognizer = UITapGestureRecognizer(target: self, action: #selector(handleTap(_:)))
		addGestureRecognizer(tapRecognizer)
	}
}
//  MARK: Interactions
public extension InteractiveTextView {
	/**
	Observes any tap made on the first instance of the provided text found within the `attributedText`.
	- Parameter text:	The portion of text to be monitored.
	- Returns:	An observable for any tap made on the text. An error will be returned if the text could not be found within `attributedText`.
	 */
	func tap(onString text: String) -> Observable<Void> {
		guard let range = attributedText.string.range(of: text) else { return .error(InteractiveTextViewError.wordNotFound) }
		let updatedText = NSMutableAttributedString(attributedString: attributedText)
		updatedText.addAttributes([interactiveAttribute: text], range: NSRange(range, in: attributedText.string))
		attributedText = updatedText
		return .create { [weak self] observer in
			guard let `self` = self else { return Disposables.create() }
			self.callbacks[text] = { observer.onNext(()) }
			return Disposables.create { self.callbacks[text] = nil }
		}
	}
}
private extension InteractiveTextView {
	@objc func handleTap(_ recognizer: UITapGestureRecognizer) {
		//	location of tap in myTextView coordinates and taking the inset into account
		var location = recognizer.location(in: self)
		location.x -= textContainerInset.left
		location.y -= textContainerInset.top
		
		//	character index at tap location
		let characterIndex = layoutManager.characterIndex(for: location, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
		
		//	if index is valid then do something
		guard characterIndex < textStorage.length else { return }
		
		// check if the tap location has a certain attribute
		guard let observedText = attributedText.attribute(interactiveAttribute, at: characterIndex, effectiveRange: nil) as? String,
			let callback = callbacks[observedText] else { return }
		
		callback()
	}
}
//  MARK: Interactive Text View Error
public enum InteractiveTextViewError: Error {
	///	The provided word could not be found within the text.
	case wordNotFound
}