use the right delegate method for footers (#394)

SkeletonView.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name         = "SkeletonView"
-  s.version      = "1.13.0"
+  s.version      = "1.15.0"
   s.summary      = "An elegant way to show users that something is happening and also prepare them to which contents he is waiting"
   s.description  = <<-DESC
   Today almost all apps have async processes, as API requests, long runing processes, etc. And while the processes are working, usually developers place a loading view to show users that something is going on.

Sources/Collections/CollectionViews/UICollectionView+CollectionSkeleton.swift

@@ -7,11 +7,18 @@
 //
 
 import UIKit
-
+ 
 extension UICollectionView: CollectionSkeleton {
     var estimatedNumberOfRows: Int {
         guard let flowlayout = collectionViewLayout as? UICollectionViewFlowLayout else { return 0 }
-        return Int(ceil(frame.height / flowlayout.itemSize.height))
+        switch flowlayout.scrollDirection {
+        case .vertical:
+            return Int(ceil(frame.height / flowlayout.itemSize.height))
+        case .horizontal:
+            return Int(ceil(frame.width / flowlayout.itemSize.width))
+        default:
+            return 0
+        }
     }
     
     var skeletonDataSource: SkeletonCollectionDataSource? {

Sources/Collections/SkeletonCollectionDelegate.swift

@@ -25,7 +25,7 @@ extension SkeletonCollectionDelegate: UITableViewDelegate {
     }
 
     func tableView(_ tableView: UITableView, viewForFooterInSection section: Int) -> UIView? {
-        headerOrFooterView(tableView, for: originalTableViewDelegate?.collectionSkeletonView(tableView, identifierForHeaderInSection: section))
+        headerOrFooterView(tableView, for: originalTableViewDelegate?.collectionSkeletonView(tableView, identifierForFooterInSection: section))
     }
 
     func tableView(_ tableView: UITableView, didEndDisplayingHeaderView view: UIView, forSection section: Int) {

Sources/Extensions/CALayer+Extensions.swift

@@ -125,8 +125,12 @@ extension CALayer {
     private func calculateNumLines(for config: SkeletonMultilinesLayerConfig) -> Int {
         let definedNumberOfLines = config.lines
         let requiredSpaceForEachLine = config.lineHeight + config.multilineSpacing
-        let calculatedNumberOfLines = Int(round(CGFloat(bounds.height - config.paddingInsets.top - config.paddingInsets.bottom) / CGFloat(requiredSpaceForEachLine)))
-        
+        let neededLines = round(CGFloat(bounds.height - config.paddingInsets.top - config.paddingInsets.bottom) / CGFloat(requiredSpaceForEachLine))
+        guard neededLines.isNormal else {
+            return 0
+        }
+
+        let calculatedNumberOfLines = Int(neededLines)
         guard calculatedNumberOfLines > 0 else {
             return 1
         }

Sources/Helpers/PrepareForSkeletonProtocol.swift

@@ -32,7 +32,8 @@ extension UILabel {
         
         // Workaround to simulate content when the label is contained in a `UIStackView`.
         if isSuperviewAStackView, bounds.height == 0 {
-            text = "This is a placeholder text to simulate content because it's contained in a stack view in order to prevent that the content size will be zero."
+            // This is a placeholder text to simulate content because it's contained in a stack view in order to prevent that the content size will be zero.
+            text = " "
         }
         
         let desiredHeight = desiredHeightBasedOnNumberOfLines

Sources/SubviewsSkeletonables.swift

@@ -14,7 +14,11 @@ extension UIView {
 
 extension UITableView {
     override var subviewsToSkeleton: [UIView] {
-        visibleCells + visibleSectionHeaders + visibleSectionFooters
+		// on `UIViewController'S onViewDidLoad`, the window is still nil.
+		// Some developer trying to call `view.showAnimatedSkeleton()`
+		// when the request or data is loading which sometimes happens before the ViewDidAppear
+		guard window != nil else { return [] }
+		return visibleCells + visibleSectionHeaders + visibleSectionFooters
     }
 }