Merge pull request #5781 from vector-im/andy/5780_indicator_context

Replace user indicator presenting view controller with context

CommonKit/Source/UserIndicators/UserIndicatorPresentationContext.swift

@@ -0,0 +1,42 @@
+// 
+// Copyright 2022 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+import UIKit
+
+/// The presentation context is used by `UserIndicatorViewPresentable`s to display content
+/// on the screen and it serves two primary purposes:
+///
+/// - abstraction on top of UIKit (passing context instead of view controllers)
+/// - immutable context passed at init with variable presenting view controller
+///   (e.g. depending on collapsed / uncollapsed iPad presentation that changes
+///   at runtime)
+public protocol UserIndicatorPresentationContext {
+    var indicatorPresentingViewController: UIViewController? { get }
+}
+
+/// A simple implementation of `UserIndicatorPresentationContext` that uses a weak reference
+/// to the passed-in view controller as the presentation context.
+public class StaticUserIndicatorPresentationContext: UserIndicatorPresentationContext {
+    // The presenting view controller will be the parent of the user indicator,
+    // and the indicator holds a strong reference to the context, so the view controller
+    // must be decleared `weak` to avoid a retain cycle
+    public private(set) weak var indicatorPresentingViewController: UIViewController?
+    
+    public init(viewController: UIViewController) {
+        self.indicatorPresentingViewController = viewController
+    }
+}

Riot/Modules/Common/UserIndicators/UserIndicatorPresenter.swift

@@ -47,26 +47,19 @@ protocol UserIndicatorTypePresenterProtocol {
 }
 
 class UserIndicatorTypePresenter: UserIndicatorTypePresenterProtocol {
-    private weak var viewController: UIViewController?
-    
-    // In the existing app architecture it is often view controllers which instantiate
-    // various presenters (errors, alerts ... ) and present on self. Since the presenting view controller
-    // needs to be passed on init, it must be declared as weak, otherwise a retain cycle would occur.
-    private var presentingViewController: UIViewController {
-        guard let viewController = viewController else {
-            MXLog.error("[UserIndicatorTypePresenter]: Presenting view controller is not available")
-            return UIViewController()
-        }
-        return viewController
-    }
-    
+    private let presentationContext: UserIndicatorPresentationContext
     let queue: UserIndicatorQueue
     
-    init(presentingViewController: UIViewController) {
-        self.viewController = presentingViewController
+    init(presentationContext: UserIndicatorPresentationContext) {
+        self.presentationContext = presentationContext
         self.queue = UserIndicatorQueue()
     }
     
+    convenience init(presentingViewController: UIViewController) {
+        let context = StaticUserIndicatorPresentationContext(viewController: presentingViewController)
+        self.init(presentationContext: context)
+    }
+    
     func present(_ type: UserIndicatorType) -> UserIndicator {
         let request = userIndicatorRequest(for: type)
         return queue.add(request)
@@ -91,7 +84,7 @@ class UserIndicatorTypePresenter: UserIndicatorTypePresenterProtocol {
                 style: .loading,
                 label: label
             ),
-            presentingViewController: presentingViewController
+            presentationContext: presentationContext
         )
         return UserIndicatorRequest(
             presenter: presenter,
@@ -102,7 +95,7 @@ class UserIndicatorTypePresenter: UserIndicatorTypePresenterProtocol {
     private func fullScreenLoadingRequest(label: String) -> UserIndicatorRequest {
         let presenter = FullscreenLoadingViewPresenter(
             label: label,
-            presentingViewController: presentingViewController
+            presentationContext: presentationContext
         )
         return UserIndicatorRequest(
             presenter: presenter,
@@ -116,7 +109,7 @@ class UserIndicatorTypePresenter: UserIndicatorTypePresenterProtocol {
                 style: .success,
                 label: label
             ),
-            presentingViewController: presentingViewController
+            presentationContext: presentationContext
         )
         return UserIndicatorRequest(
             presenter: presenter,

Riot/Modules/Common/UserIndicators/ViewPresenters/FullscreenLoadingViewPresenter.swift

@@ -22,18 +22,18 @@ import UIKit
 /// It is managed by a `UserIndicator`, meaning the `present` and `dismiss` methods will be called when the parent `UserIndicator` starts or completes.
 class FullscreenLoadingViewPresenter: UserIndicatorViewPresentable {
     private let label: String
-    private weak var viewController: UIViewController?
+    private let presentationContext: UserIndicatorPresentationContext
     private weak var view: UIView?
     private var animator: UIViewPropertyAnimator?
     
-    init(label: String, presentingViewController: UIViewController) {
+    init(label: String, presentationContext: UserIndicatorPresentationContext) {
         self.label = label
-        self.viewController = presentingViewController
+        self.presentationContext = presentationContext
     }
 
     func present() {
         // Find the current top navigation controller
-        var presentingController: UIViewController? = viewController
+        var presentingController: UIViewController? = presentationContext.indicatorPresentingViewController
         while presentingController?.navigationController != nil {
             presentingController = presentingController?.navigationController
         }

Riot/Modules/Common/UserIndicators/ViewPresenters/ToastViewPresenter.swift

@@ -27,17 +27,17 @@ class ToastViewPresenter: UserIndicatorViewPresentable {
     }
     
     private let viewState: ToastViewState
-    private weak var viewController: UIViewController?
+    private let presentationContext: UserIndicatorPresentationContext
     private weak var view: UIView?
     private var animator: UIViewPropertyAnimator?
     
-    init(viewState: ToastViewState, presentingViewController: UIViewController) {
+    init(viewState: ToastViewState, presentationContext: UserIndicatorPresentationContext) {
         self.viewState = viewState
-        self.viewController = presentingViewController
+        self.presentationContext = presentationContext
     }
 
     func present() {
-        guard let viewController = viewController else {
+        guard let viewController = presentationContext.indicatorPresentingViewController else {
             return
         }
         

Riot/Modules/SplitView/SplitViewCoordinator.swift

@@ -16,6 +16,7 @@
 
 import Foundation
 import MatrixSDK
+import CommonKit
 
 /// SplitViewCoordinatorParameters input parameters
 class SplitViewCoordinatorParameters {
@@ -104,7 +105,13 @@ final class SplitViewCoordinator: NSObject, SplitViewCoordinatorType {
             // Setup split view controller
             self.splitViewController.viewControllers = [tabBarCoordinator.toPresentable(), detailNavigationController]
             
-            updateUserIndicatorPresenter()
+            // Setup detail user indicator presenter
+            let context = SplitViewUserIndicatorPresentationContext(
+                splitViewController: splitViewController,
+                tabBarCoordinator: tabBarCoordinator,
+                detailNavigationController: detailNavigationController
+            )
+            detailUserIndicatorPresenter = UserIndicatorTypePresenter(presentationContext: context)
                     
             self.add(childCoordinator: tabBarCoordinator)
             
@@ -260,16 +267,6 @@ final class SplitViewCoordinator: NSObject, SplitViewCoordinatorType {
             }
         }
     }
-    
-    private func updateUserIndicatorPresenter() {
-        guard let tabBarCoordinator = tabBarCoordinator, let detailNavigationController = detailNavigationController else {
-            MXLog.debug("[SplitViewCoordinator]: Missing tab bar or detail coordinator, cannot update user indicator presenter")
-            return
-        }
-        
-        let presentingViewController = splitViewController.isCollapsed ? tabBarCoordinator.toPresentable() : detailNavigationController
-        detailUserIndicatorPresenter = UserIndicatorTypePresenter(presentingViewController: presentingViewController)
-    }
 }
 
 // MARK: - UISplitViewControllerDelegate
@@ -299,8 +296,6 @@ extension SplitViewCoordinator: UISplitViewControllerDelegate {
         // Restore detail navigation controller with placeholder as root
         self.resetDetailNavigationController(animated: false)
         
-        updateUserIndicatorPresenter()
-        
         // Return up to date detail navigation controller
         // In any cases `detailNavigationController` will be used as secondary view of the split view controller.
         return self.detailNavigationController
@@ -311,7 +306,6 @@ extension SplitViewCoordinator: UISplitViewControllerDelegate {
     /// or true to indicate that you do not want the split view controller to do anything with the secondary view controller.
     /// Sample case: large iPhone goes from landscape to portrait.
     func splitViewController(_ splitViewController: UISplitViewController, collapseSecondary secondaryViewController: UIViewController, onto primaryViewController: UIViewController) -> Bool {
-        updateUserIndicatorPresenter()
         
         // If the secondary view is the placeholder screen do not merge the secondary into the primary.
         // Note: In this case, the secondaryViewController will be automatically discarded.

Riot/Modules/SplitView/SplitViewUserIndicatorPresentationContext.swift

@@ -0,0 +1,46 @@
+// 
+// Copyright 2022 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+import CommonKit
+
+class SplitViewUserIndicatorPresentationContext: UserIndicatorPresentationContext {
+    private weak var splitViewController: UISplitViewController?
+    private weak var tabBarCoordinator: TabBarCoordinator?
+    private weak var detailNavigationController: UINavigationController?
+    
+    init(
+        splitViewController: UISplitViewController,
+        tabBarCoordinator: TabBarCoordinator,
+        detailNavigationController: UINavigationController
+    ) {
+        self.splitViewController = splitViewController
+        self.tabBarCoordinator = tabBarCoordinator
+        self.detailNavigationController = detailNavigationController
+    }
+    
+    var indicatorPresentingViewController: UIViewController? {
+        guard
+            let splitViewController = splitViewController,
+            let tabBarCoordinator = tabBarCoordinator,
+            let detailNavigationController = detailNavigationController
+        else {
+            MXLog.debug("[SplitViewCoordinator]: Missing tab bar or detail coordinator, cannot update user indicator presenter")
+            return nil
+        }
+        return splitViewController.isCollapsed ? tabBarCoordinator.toPresentable() : detailNavigationController
+    }
+}

changelog.d/5780.change

@@ -0,0 +1 @@
+Activity Indicators: Replace user indicator presenting view controller with context