Fix iOS steps

Author: cbush

source/includes/steps-tutorial-ios-swift.yaml

@@ -120,14 +120,16 @@ content: |
   field for email and password, sign in and sign up buttons, and an activity
   indicator to show when the app is handling an authentication request.
 
-  First, let's implement the ``signUp()`` method to register a new user:
+  First, let's implement the ``signUp()`` method to register a new user, which
+  uses the email/password authentication provider of the Realm app to register a
+  new user:
 
   .. literalinclude:: /tutorial/generated/code/final/WelcomeViewController.codeblock.sign-up.swift
      :language: swift
 
-  Now, implement the ``signIn()`` method to log in with an existing user. Once
-  logged in successfully, open the user realm and navigate to the
-  ProjectsViewController:
+  Now, implement the ``signIn()`` method to log in with an existing user using
+  email/password credentials. Once logged in successfully, open the user realm
+  and navigate to the ProjectsViewController:
 
   .. literalinclude:: /tutorial/generated/code/final/WelcomeViewController.codeblock.sign-in.swift
      :language: swift
@@ -152,6 +154,15 @@ content: |
   .. literalinclude:: /tutorial/generated/code/final/ProjectsViewController.codeblock.user-in-realm-notification.swift
      :language: swift
 
+  Whenever we observe a realm, collection, or object, we receive a notification
+  token that we must retain as long as we want to keep observing that object.
+  Once we are done observing, for example because the user navigated to another
+  screen, we should invalidate that token. One convenient place to do so is in
+  the deinit method of the view controller:
+
+  .. literalinclude:: /tutorial/generated/code/final/ProjectsViewController.codeblock.invalidate-token.swift
+     :language: swift
+
   Let's provide a way for a user to log out and get back to the
   WelcomeViewController. The ``viewDidLoad()`` method hooks up the Log Out
   button at the top of the view to the ``logOutButtonDidClick()`` method. We can

source/tutorial/generated/code/final/ProjectsViewController.codeblock.number-of-rows-in-section.swift

@@ -1,16 +1,4 @@
 func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
     // You always have at least one project (your own)
     return userData?.memberOf.count ?? 1
-}
-
-// :code-block-start: cell-for-row-at
-func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
-    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell") ?? UITableViewCell(style: .default, reuseIdentifier: "Cell")
-    cell.selectionStyle = .none
-
-    // User data may not have loaded yet. You always have your own project.
-    let projectName = userData?.memberOf[indexPath.row].name ?? "My Project"
-    cell.textLabel?.text = projectName
-    
-    return cell
 }

tutorial/swift-ios/Task Tracker/ProjectsViewController.swift

@@ -65,6 +65,30 @@ class ProjectsViewController: UIViewController, UITableViewDelegate, UITableView
         navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Log Out", style: .plain, target: self, action: #selector(logOutButtonDidClick))
     }
 
+    // :code-block-start: log-out-button-did-click
+    @objc func logOutButtonDidClick() {
+        let alertController = UIAlertController(title: "Log Out", message: "", preferredStyle: .alert);
+        alertController.addAction(UIAlertAction(title: "Yes, Log Out", style: .destructive, handler: {
+            alert -> Void in
+            print("Logging out...");
+            // :hide-start:
+            app.currentUser()?.logOut() { (error) in
+                DispatchQueue.main.sync {
+                    print("Logged out!");
+                    self.navigationController?.popViewController(animated: true)
+                }
+            }
+            // :replace-with:
+            // // TODO: log out the app's currentUser, then, on the main thread, pop this
+            // // view controller from the navigation controller to navigate back to
+            // // the WelcomeViewController.
+            // :hide-end:
+        }))
+        alertController.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
+        self.present(alertController, animated: true, completion: nil)
+    }
+    // :code-block-end:
+
     // :code-block-start: number-of-rows-in-section
     func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
         // :hide-start:
@@ -78,6 +102,7 @@ class ProjectsViewController: UIViewController, UITableViewDelegate, UITableView
         // return 0
         // :hide-end:
     }
+    // :code-block-end:
 
     // :code-block-start: cell-for-row-at
     func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
@@ -125,27 +150,4 @@ class ProjectsViewController: UIViewController, UITableViewDelegate, UITableView
     }
     // :code-block-end:
 
-    // :code-block-start: log-out-button-did-click
-    @objc func logOutButtonDidClick() {
-        let alertController = UIAlertController(title: "Log Out", message: "", preferredStyle: .alert);
-        alertController.addAction(UIAlertAction(title: "Yes, Log Out", style: .destructive, handler: {
-            alert -> Void in
-            print("Logging out...");
-            // :hide-start:
-            app.currentUser()?.logOut() { (error) in
-                DispatchQueue.main.sync {
-                    print("Logged out!");
-                    self.navigationController?.popViewController(animated: true)
-                }
-            }
-            // :replace-with:
-            // // TODO: log out the app's currentUser, then, on the main thread, pop this
-            // // view controller from the navigation controller to navigate back to
-            // // the WelcomeViewController.
-            // :hide-end:
-        }))
-        alertController.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
-        self.present(alertController, animated: true, completion: nil)
-    }
-    // :code-block-end:
 }