From 4c8d796b8a7eeae3a86ff7506de463fbed0faf80 Mon Sep 17 00:00:00 2001
From: Zheng <49819455+zjohnzheng@users.noreply.github.com>
Date: Tue, 7 Jul 2020 12:03:31 -0700
Subject: [PATCH] Allow swiping on iOS 13 page sheet

Conform to gestureRecognizer(_:shouldBeRequiredToFailBy:)
Details at https://developer.apple.com/documentation/uikit/uigesturerecognizerdelegate/1624222-gesturerecognizer
---
 Source/GestureControl/GestureControl.swift | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/Source/GestureControl/GestureControl.swift b/Source/GestureControl/GestureControl.swift
index 0c01a36..c9f504a 100644
--- a/Source/GestureControl/GestureControl.swift
+++ b/Source/GestureControl/GestureControl.swift
@@ -26,10 +26,12 @@ public class GestureControl: UIView {
 
         swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(GestureControl.swipeHandler(_:)))
         swipeLeft.direction = .left
+        swipeLeft.delegate = self  /// reference the gesture recognizer delegate
         addGestureRecognizer(swipeLeft)
 
         swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(GestureControl.swipeHandler(_:)))
         swipeRight.direction = .right
+        swipeRight.delegate = self /// reference the gesture recognizer delegate
         addGestureRecognizer(swipeRight)
 
         translatesAutoresizingMaskIntoConstraints = false
@@ -50,6 +52,18 @@ public class GestureControl: UIView {
     }
 }
 
+// MARK: Gesture recognizer delegate
+/// the default modal presentation style in iOS 13 is a page sheet
+/// if Paper Onboarding is presented as a page sheet, this function is **required to enable swiping**
+/// because there is a built-in gesture (that dismisses the page sheet) which conflicts with the swipe gesture
+///
+/// with this function, **both the swipe gesture and the built-in gesture work!**
+extension GestureControl: UIGestureRecognizerDelegate {
+    public func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldBeRequiredToFailBy otherGestureRecognizer: UIGestureRecognizer) -> Bool {
+        return true
+    }
+}
+
 // MARK: actions
 
 extension GestureControl {