Migrate to UINavigationBarAppearance API

3 files changed, 59 insertions, 35 deletions

diff --git a/ios/MullvadVPN/CustomNavigationBar.swift b/ios/MullvadVPN/CustomNavigationBar.swift
index 2c9be14f39..51a7655254 100644
--- a/ios/MullvadVPN/CustomNavigationBar.swift
+++ b/ios/MullvadVPN/CustomNavigationBar.swift
@@ -10,16 +10,17 @@ import UIKit
 
 class CustomNavigationBar: UINavigationBar {
 
-    private static let setupAppearanceOnce: Void = {
-        let buttonAppearance = UIBarButtonItem.appearance(whenContainedInInstancesOf: [CustomNavigationBar.self])
-        buttonAppearance.setBackButtonTitlePositionAdjustment(UIOffset(horizontal: 4, vertical: 0), for: .default)
+    private static let setupAppearanceForIOS12Once: Void = {
+        if #available(iOS 13, *) {
+            // no-op
+        } else {
+            let buttonAppearance = UIBarButtonItem.appearance(whenContainedInInstancesOf: [CustomNavigationBar.self])
+            buttonAppearance.setBackButtonTitlePositionAdjustment(UIOffset(horizontal: 4, vertical: 0), for: .default)
+        }
     }()
 
-    var prefersOpaqueBackground: Bool {
-        didSet {
-            setOpaqueBackgroundAppearance(prefersOpaqueBackground)
-        }
-    }
+    private let customBackIndicatorImage = UIImage(named: "IconBack")
+    private let customBackIndicatorTransitionMask = UIImage(named: "IconBackTransitionMask")
 
     // Returns the distance from the title label to the bottom of navigation bar
     var titleLabelBottomInset: CGFloat {
@@ -41,13 +42,7 @@ class CustomNavigationBar: UINavigationBar {
     }
 
     override init(frame: CGRect) {
-        Self.setupAppearanceOnce
-
-        if #available(iOS 13, *) {
-            prefersOpaqueBackground = false
-        } else {
-            prefersOpaqueBackground = true
-        }
+        Self.setupAppearanceForIOS12Once
 
         super.init(frame: frame)
 
@@ -56,28 +51,61 @@ class CustomNavigationBar: UINavigationBar {
         margins.right = UIMetrics.contentLayoutMargins.right
         layoutMargins = margins
 
-        backIndicatorImage = UIImage(named: "IconBack")
-        backIndicatorTransitionMaskImage = UIImage(named: "IconBackTransitionMask")
-
-        setOpaqueBackgroundAppearance(prefersOpaqueBackground)
+        setupNavigationBarAppearance()
     }
 
     required init?(coder: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
 
-    private func setOpaqueBackgroundAppearance(_ flag: Bool) {
-        if flag {
+    private func setupNavigationBarAppearance() {
+        backgroundColor = .secondaryColor
+        isTranslucent = false
+
+        if #available(iOS 13, *) {
+            standardAppearance = makeNavigationBarAppearance()
+            scrollEdgeAppearance = makeNavigationBarAppearance()
+        } else {
+            backIndicatorImage = customBackIndicatorImage
+            backIndicatorTransitionMaskImage = customBackIndicatorTransitionMask
             barTintColor = .secondaryColor
-            backgroundColor = .secondaryColor
+            titleTextAttributes = [.foregroundColor: UIColor.white]
             shadowImage = UIImage()
-            isTranslucent = false
+        }
+    }
+
+    @available(iOS 13, *)
+    private func makeNavigationBarAppearance() -> UINavigationBarAppearance {
+        let textAttributes: [NSAttributedString.Key: Any] = [.foregroundColor: UIColor.white]
+
+        let navigationBarAppearance = UINavigationBarAppearance()
+        navigationBarAppearance.configureWithTransparentBackground()
+        navigationBarAppearance.titleTextAttributes = textAttributes
+        navigationBarAppearance.largeTitleTextAttributes = textAttributes
+
+        let plainBarButtonAppearance = UIBarButtonItemAppearance(style: .plain)
+        plainBarButtonAppearance.normal.titleTextAttributes = textAttributes
+
+        let doneBarButtonAppearance = UIBarButtonItemAppearance(style: .done)
+        doneBarButtonAppearance.normal.titleTextAttributes = textAttributes
+
+        let backButtonAppearance = UIBarButtonItemAppearance(style: .plain)
+        backButtonAppearance.normal.titleTextAttributes = textAttributes
+        backButtonAppearance.normal.titlePositionAdjustment = UIOffset(horizontal: 4, vertical: 0)
+
+        navigationBarAppearance.buttonAppearance = plainBarButtonAppearance
+        navigationBarAppearance.doneButtonAppearance = doneBarButtonAppearance
+        navigationBarAppearance.backButtonAppearance = backButtonAppearance
+
+        if #available(iOS 14, *) {
+            navigationBarAppearance.setBackIndicatorImage(customBackIndicatorImage, transitionMaskImage: customBackIndicatorTransitionMask)
         } else {
-            barTintColor = nil
-            backgroundColor = nil
-            shadowImage = nil
-            isTranslucent = true
+            // Bug: on iOS 13 setBackIndicatorImage accepts parameters in backward order
+            // https://stackoverflow.com/a/58171229/351305
+            navigationBarAppearance.setBackIndicatorImage(customBackIndicatorTransitionMask, transitionMaskImage: customBackIndicatorImage)
         }
+
+        return navigationBarAppearance
     }
 
 }
diff --git a/ios/MullvadVPN/SelectLocationNavigationController.swift b/ios/MullvadVPN/SelectLocationNavigationController.swift
index 13da20e934..46df46698d 100644
--- a/ios/MullvadVPN/SelectLocationNavigationController.swift
+++ b/ios/MullvadVPN/SelectLocationNavigationController.swift
@@ -14,18 +14,12 @@ class SelectLocationNavigationController: UINavigationController {
     init(contentController: SelectLocationViewController) {
         super.init(navigationBarClass: CustomNavigationBar.self, toolbarClass: nil)
 
-        navigationBar.barStyle = .black
-        navigationBar.tintColor = .white
-        navigationBar.prefersLargeTitles = false
-
-        (navigationBar as? CustomNavigationBar)?.prefersOpaqueBackground = true
-
         self.viewControllers = [contentController]
     }
 
     override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
-        // This override has to exist to prevent crash on iOS 12 where `UINavigationController`
-        // calls `self.init(nibName:bundle:)` internally.
+        // This initializer exists to prevent crash on iOS 12.
+        // See: https://stackoverflow.com/a/38335090/351305
         super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
     }
 
diff --git a/ios/MullvadVPN/SelectLocationViewController.swift b/ios/MullvadVPN/SelectLocationViewController.swift
index 2e17e44a15..a5cffcc452 100644
--- a/ios/MullvadVPN/SelectLocationViewController.swift
+++ b/ios/MullvadVPN/SelectLocationViewController.swift
@@ -52,6 +52,8 @@ class SelectLocationViewController: UIViewController, UITableViewDelegate {
     override func viewDidLoad() {
         super.viewDidLoad()
 
+        navigationItem.largeTitleDisplayMode = .never
+
         let tableView = UITableView(frame: view.bounds, style: .plain)
         tableView.translatesAutoresizingMaskIntoConstraints = false
         tableView.backgroundColor = .clear