Scroll ChatList to top if already visible (#2125)

DcCore/DcCore/Extensions/UITableView+Extensions.swift

@@ -1,14 +1,14 @@
 import UIKit
 
 extension UITableView {
-    public func scrollToTop() {
-        let numberOfSections = self.numberOfSections
-        if numberOfSections > 0 {
-            let numberOfRows = self.numberOfRows(inSection: 0)
-            if numberOfRows > 0 {
-                let indexPath = IndexPath(row: 0, section: 0)
-                self.scrollToRow(at: indexPath, at: UITableView.ScrollPosition.top, animated: false)
-            }
-        }
+  public func scrollToTop(animated: Bool = false) {
+    let numberOfSections = self.numberOfSections
+    if numberOfSections > 0 {
+      let numberOfRows = self.numberOfRows(inSection: 0)
+      if numberOfRows > 0 {
+        let indexPath = IndexPath(row: 0, section: 0)
+        self.scrollToRow(at: indexPath, at: UITableView.ScrollPosition.top, animated: animated)
+      }
     }
+  }
 }

deltachat-ios/Coordinator/AppCoordinator.swift

@@ -4,7 +4,7 @@ import MobileCoreServices
 import DcCore
 
 // MARK: - AppCoordinator
-class AppCoordinator {
+class AppCoordinator: NSObject {
 
     private let window: UIWindow
     private let dcAccounts: DcAccounts
@@ -30,7 +30,7 @@ class AppCoordinator {
         let chatsNavController = createChatsNavigationController()
         let settingsNavController = createSettingsNavigationController()
         let tabBarController = UITabBarController()
-        tabBarController.delegate = appStateRestorer
+        tabBarController.delegate = self
         tabBarController.viewControllers = [allMediaNavController, qrNavController, chatsNavController, settingsNavController]
         tabBarController.tabBar.tintColor = DcColors.primary
         return tabBarController
@@ -39,29 +39,29 @@ class AppCoordinator {
     private func createQrNavigationController() -> UINavigationController {
         let root = QrPageController(dcAccounts: dcAccounts)
         let nav = UINavigationController(rootViewController: root)
-        let settingsImage: UIImage?
+        let qrCodeTabImage: UIImage?
         if #available(iOS 13.0, *) {
-            settingsImage = UIImage(systemName: "qrcode")
+            qrCodeTabImage = UIImage(systemName: "qrcode")
         } else {
-            settingsImage = UIImage(named: "qr_code")
+            qrCodeTabImage = UIImage(named: "qr_code")
         }
-        nav.tabBarItem = UITabBarItem(title: String.localized("qr_code"), image: settingsImage, tag: qrTab)
+        nav.tabBarItem = UITabBarItem(title: String.localized("qr_code"), image: qrCodeTabImage, tag: qrTab)
         return nav
     }
 
     private func createAllMediaNavigationController() -> UINavigationController {
         let root = AllMediaViewController(dcContext: dcAccounts.getSelected())
         let nav = UINavigationController(rootViewController: root)
-        let settingsImage = UIImage(named: "photo.on.rectangle")
-        nav.tabBarItem = UITabBarItem(title: String.localized("menu_all_media"), image: settingsImage, tag: chatsTab)
+        let allMediaTabImage = UIImage(named: "photo.on.rectangle")
+        nav.tabBarItem = UITabBarItem(title: String.localized("menu_all_media"), image: allMediaTabImage, tag: allMediaTab)
         return nav
     }
 
     private func createChatsNavigationController() -> UINavigationController {
         let root = ChatListViewController(dcContext: dcAccounts.getSelected(), dcAccounts: dcAccounts, isArchive: false)
         let nav = UINavigationController(rootViewController: root)
-        let settingsImage = UIImage(named: "ic_chat")
-        nav.tabBarItem = UITabBarItem(title: String.localized("pref_chats"), image: settingsImage, tag: chatsTab)
+        let chatTabImage = UIImage(named: "ic_chat")
+        nav.tabBarItem = UITabBarItem(title: String.localized("pref_chats"), image: chatTabImage, tag: chatsTab)
         return nav
     }
 
@@ -83,6 +83,7 @@ class AppCoordinator {
         self.window = window
         self.dcAccounts = dcAccounts
         let dcContext = dcAccounts.getSelected()
+        super.init()
         initializeRootController()
 
         let lastActiveTab = appStateRestorer.restoreLastActiveTab()
@@ -272,3 +273,20 @@ class AppCoordinator {
         presentTabBarController()
     }
 }
+
+extension AppCoordinator: UITabBarControllerDelegate {
+    func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
+        if let navigationController = viewController as? UINavigationController,
+           let chatListViewController = navigationController.viewControllers.first as? ChatListViewController,
+           let chatsTab = tabBarController.selectedViewController as? UINavigationController,
+           chatsTab.topViewController == chatListViewController {
+            chatListViewController.tableView.scrollToTop(animated: true)
+        }
+
+        return true
+    }
+
+    func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
+        appStateRestorer.tabBarController(tabBarController, didSelect: viewController)
+    }
+}

deltachat-ios/Handler/AppStateRestorer.swift

@@ -1,6 +1,6 @@
 import UIKit
 
-class AppStateRestorer: NSObject, UITabBarControllerDelegate {
+class AppStateRestorer {
 
     private let lastActiveTabKey = "last_active_tab2"
     private let lastActiveChatId = "last_active_chat_id"
@@ -16,8 +16,6 @@ class AppStateRestorer: NSObject, UITabBarControllerDelegate {
         case firstLaunch = 0
     }
 
-    private override init() {}
-
     static let shared: AppStateRestorer = AppStateRestorer()
 
     func restoreLastActiveTab() -> Int {