Only set tap gesture if needed

Author: Frank Lehmann

Sources/LazyPager/ZoomableView.swift

@@ -112,19 +112,23 @@ class ZoomableView<Element, Content: View>: UIScrollView, UIScrollViewDelegate {
             v.heightAnchor.constraint(equalToConstant: constant)
         ])
 
-        let singleTapGesture = UITapGestureRecognizer(target: self, action: #selector(singleTap(_:)))
-        singleTapGesture.numberOfTapsRequired = 1
-        singleTapGesture.numberOfTouchesRequired = 1
-        addGestureRecognizer(singleTapGesture)
+        var singleTapGesture: UITapGestureRecognizer?
+        if config.tapCallback != nil {
+            let gesture = UITapGestureRecognizer(target: self, action: #selector(singleTap(_:)))
+            gesture.numberOfTapsRequired = 1
+            gesture.numberOfTouchesRequired = 1
+            addGestureRecognizer(gesture)
+            singleTapGesture = gesture
+        }
 
         func setupDoubleTapGesture() {
             let doubleTapRecognizer = UITapGestureRecognizer(target: self, action: #selector(onDoubleTap(_:)))
             doubleTapRecognizer.numberOfTapsRequired = 2
             doubleTapRecognizer.numberOfTouchesRequired = 1
-            addGestureRecognizer(doubleTapRecognizer)
-            
-            singleTapGesture.require(toFail: doubleTapRecognizer)
+            addGestureRecognizer(doubleTapRecognizer)            
+            singleTapGesture?.require(toFail: doubleTapRecognizer)
         }
+        
         if case .scale = doubleTap {
             setupDoubleTapGesture()
         } else if config.doubleTapCallback != nil {