calculate cache asyncronously. Closes #274

Author: merlos

Diff for: OpenGpxTracker/PreferencesTableViewController.swift

@@ -84,8 +84,24 @@ class PreferencesTableViewController: UITableViewController, UINavigationBarDele
                                         action: #selector(PreferencesTableViewController.closePreferencesTableViewController))
         self.navigationItem.rightBarButtonItems = [shareItem]
 
-        let fileSize = cache.diskCache.fileSize ?? 0
-        cachedSize = Int(fileSize).asFileSize()
+        //let fileSize = cache.diskCache.fileSize ?? 0
+        //cachedSize = Int(fileSize).asFileSize()
+        // Set a temporary value for cachedSize
+        cachedSize = "Calculating..."
+        print("PreferencesTableViewConroller: Starting cache calculation")
+        // Perform the file size calculation asynchronously
+        DispatchQueue.global(qos: .background).async {
+            let fileSize = self.cache.diskCache.fileSize ?? 0
+            self.cachedSize = Int(fileSize).asFileSize()
+
+            // Update the cachedSize on the main thread once the operation is complete
+            DispatchQueue.main.async {
+                print("PreferencesTableViewController: Completing cache calculation")
+                if let cell = self.tableView.cellForRow(at: IndexPath(row: kUseOfflineCacheCell, section: kCacheSection)) {
+                    cell.detailTextLabel?.text = self.cachedSize
+                }
+            }
+        }
     }
 
     /// Close this controller.

Diff for: OpenGpxTracker/ViewController.swift

@@ -977,23 +977,10 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
     ///
     @objc func openPreferencesTableViewController() {
         print("openPreferencesTableViewController")
-
-        // Show loading toast
-        Toast.showLoading("Loading Preferences...")
-
-        // Perform all operations on the main thread
-        DispatchQueue.main.async {
-            // Simulate a delay for testing (remove in production)
-            //Thread.sleep(forTimeInterval: 4.5)
-
-            let vc = PreferencesTableViewController(style: .grouped)
-            vc.delegate = self
-            let navController = UINavigationController(rootViewController: vc)
-
-            // Hide the loading toast and present the view controller
-            Toast.hideLoading()
-            self.present(navController, animated: true)
-        }
+        let vc = PreferencesTableViewController(style: .grouped)
+        vc.delegate = self
+        let navController = UINavigationController(rootViewController: vc)
+        self.present(navController, animated: true)
     }
 
     ///