Remove boolean for activity indicator

Author: ywsang

TCAT/Controllers/AllStopsTableViewController.swift

@@ -21,8 +21,7 @@ class AllStopsTableViewController: UITableViewController {
     var unwindAllStopsTVCDelegate: UnwindAllStopsTVCDelegate?
     var height: CGFloat?
     var currentChar: Character?
-    var showActivityIndicator = false
-    var activityIndicator: UIActivityIndicatorView!
+    var activityIndicator: UIActivityIndicatorView?
 
     override func viewWillLayoutSubviews() {
         if let y = navigationController?.navigationBar.frame.maxY {
@@ -57,8 +56,6 @@ class AllStopsTableViewController: UITableViewController {
         tableView.tableFooterView = UIView()
         // Set top of table view to align with scroll view
         tableView.contentOffset = .zero
-
-        setUpActivityIndicator()
     }
 
     // MARK: TableView DataSource
@@ -194,25 +191,23 @@ class AllStopsTableViewController: UITableViewController {
 
 // MARK: DZNEmptyDataSet 
 extension AllStopsTableViewController: DZNEmptyDataSetSource, DZNEmptyDataSetDelegate {
-
     func setUpActivityIndicator() {
         activityIndicator = UIActivityIndicatorView(style: UIActivityIndicatorView.Style.gray)
-        view.addSubview(activityIndicator!)
-        activityIndicator.snp.makeConstraints { (make) in
-            make.centerX.equalToSuperview()
-            make.centerY.equalToSuperview()
+        if let activityIndicator = activityIndicator {
+            view.addSubview(activityIndicator)
+            activityIndicator.snp.makeConstraints { (make) in
+                make.centerX.equalToSuperview()
+                make.centerY.equalToSuperview()
+            }
         }
     }
 
     func image(forEmptyDataSet scrollView: UIScrollView!) -> UIImage! {
-        if showActivityIndicator {
-            return nil
-        }
-        return #imageLiteral(resourceName: "emptyPin")
+        return activityIndicator != nil ? nil : #imageLiteral(resourceName: "emptyPin")
     }
 
     func description(forEmptyDataSet scrollView: UIScrollView!) -> NSAttributedString! {
-        if showActivityIndicator {
+        if let _ = activityIndicator {
             return nil
         }
         let title = "Couldn't Get Stops"
@@ -221,7 +216,7 @@ extension AllStopsTableViewController: DZNEmptyDataSetSource, DZNEmptyDataSetDel
     }
 
     func buttonTitle(forEmptyDataSet scrollView: UIScrollView!, for state: UIControl.State) -> NSAttributedString! {
-        if showActivityIndicator {
+        if let _ = activityIndicator {
             return nil
         }
         let title = "Retry"
@@ -230,14 +225,16 @@ extension AllStopsTableViewController: DZNEmptyDataSetSource, DZNEmptyDataSetDel
     }
 
     func emptyDataSet(_ scrollView: UIScrollView!, didTap didTapButton: UIButton!) {
-        showActivityIndicator = true
-        tableView.reloadData()
         setUpActivityIndicator()
-        activityIndicator.startAnimating()
-
-        retryNetwork {() -> Void in
+        if let activityIndicator = activityIndicator {
+            tableView.reloadData()
+            activityIndicator.startAnimating()
+        }
+        retryNetwork { () -> Void in
             self.setUpTableOnRetry()
-            self.activityIndicator.stopAnimating()
+            if let activityIndicator = self.activityIndicator {
+                activityIndicator.stopAnimating()
+            }
         }
     }