Add tapping the active tab bar item to scroll to top

Closes #106

Tusker.xcodeproj/project.pbxproj

@@ -118,6 +118,7 @@
 		D63F9C6C241C50B9004C03CF /* ComposeAttachmentTableViewCell.xib in Resources */ = {isa = PBXBuildFile; fileRef = D63F9C6A241C50B9004C03CF /* ComposeAttachmentTableViewCell.xib */; };
 		D63F9C6E241D2D85004C03CF /* CompositionAttachment.swift in Sources */ = {isa = PBXBuildFile; fileRef = D63F9C6D241D2D85004C03CF /* CompositionAttachment.swift */; };
 		D640D76922BAF5E6004FBE69 /* DomainBlocks.plist in Resources */ = {isa = PBXBuildFile; fileRef = D640D76822BAF5E6004FBE69 /* DomainBlocks.plist */; };
+		D6412B0324AFF6A600F5412E /* TabBarScrollableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6412B0224AFF6A600F5412E /* TabBarScrollableViewController.swift */; };
 		D641C773213CAA25004B4513 /* NotificationsTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D641C772213CAA25004B4513 /* NotificationsTableViewController.swift */; };
 		D641C77F213DC78A004B4513 /* InlineTextAttachment.swift in Sources */ = {isa = PBXBuildFile; fileRef = D641C77E213DC78A004B4513 /* InlineTextAttachment.swift */; };
 		D6434EB3215B1856001A919A /* XCBRequest.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6434EB2215B1856001A919A /* XCBRequest.swift */; };
@@ -422,6 +423,7 @@
 		D63F9C6A241C50B9004C03CF /* ComposeAttachmentTableViewCell.xib */ = {isa = PBXFileReference; lastKnownFileType = file.xib; path = ComposeAttachmentTableViewCell.xib; sourceTree = "<group>"; };
 		D63F9C6D241D2D85004C03CF /* CompositionAttachment.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CompositionAttachment.swift; sourceTree = "<group>"; };
 		D640D76822BAF5E6004FBE69 /* DomainBlocks.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = DomainBlocks.plist; sourceTree = "<group>"; };
+		D6412B0224AFF6A600F5412E /* TabBarScrollableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TabBarScrollableViewController.swift; sourceTree = "<group>"; };
 		D641C772213CAA25004B4513 /* NotificationsTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationsTableViewController.swift; sourceTree = "<group>"; };
 		D641C77E213DC78A004B4513 /* InlineTextAttachment.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = InlineTextAttachment.swift; sourceTree = "<group>"; };
 		D6434EB2215B1856001A919A /* XCBRequest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XCBRequest.swift; sourceTree = "<group>"; };
@@ -1238,6 +1240,7 @@
 				D693DE5623FE1A6A0061E07D /* EnhancedNavigationViewController.swift */,
 				D693DE5823FE24300061E07D /* InteractivePushTransition.swift */,
 				D6DFC69D242C490400ACC392 /* TrackpadScrollGestureRecognizer.swift */,
+				D6412B0224AFF6A600F5412E /* TabBarScrollableViewController.swift */,
 			);
 			path = Utilities;
 			sourceTree = "<group>";
@@ -1701,6 +1704,7 @@
 				0427033A22B31269000D31B6 /* AdvancedPrefsView.swift in Sources */,
 				D626493C23C1000300612E6E /* AlbumTableViewCell.swift in Sources */,
 				D60E2F292442372B005F8713 /* AccountMO.swift in Sources */,
+				D6412B0324AFF6A600F5412E /* TabBarScrollableViewController.swift in Sources */,
 				D6757A822157E8FA00721E32 /* XCBSession.swift in Sources */,
 				D6EBF01723C55E0D00AE061B /* UISceneSession+MastodonController.swift in Sources */,
 				04DACE8C212CB14B009840C4 /* MainTabBarViewController.swift in Sources */,

Tusker/Screens/Main/MainTabBarViewController.swift

@@ -57,6 +57,13 @@ class MainTabBarViewController: UITabBarController, UITabBarControllerDelegate {
             presentCompose()
             return false
         }
+        if viewController == viewControllers![selectedIndex],
+           let nav = viewController as? UINavigationController,
+           nav.viewControllers.count == 1,
+           let scrollableVC = nav.viewControllers.first as? TabBarScrollableViewController {
+            scrollableVC.tabBarScrollToTop()
+            return false
+        }
         return true
     }
     

Tusker/Screens/Utilities/EnhancedTableViewController.swift

@@ -95,3 +95,13 @@ extension EnhancedTableViewController {
     }
     
 }
+
+extension EnhancedTableViewController: TabBarScrollableViewController {
+    func tabBarScrollToTop() {
+        if scrollViewShouldScrollToTop(tableView) {
+            let topOffset = CGPoint(x: 0, y: -tableView.adjustedContentInset.top)
+            tableView.setContentOffset(topOffset, animated: true)
+            scrollViewDidScrollToTop(tableView)
+        }
+    }
+}

Tusker/Screens/Utilities/SegmentedPageViewController.swift

@@ -63,3 +63,11 @@ class SegmentedPageViewController: UIPageViewController, UIPageViewControllerDel
     }
 
 }
+
+extension SegmentedPageViewController: TabBarScrollableViewController {
+    func tabBarScrollToTop() {
+        if let scrollableVC = pageControllers[currentIndex] as? TabBarScrollableViewController {
+            scrollableVC.tabBarScrollToTop()
+        }
+    }
+}

Tusker/Screens/Utilities/TabBarScrollableViewController.swift

@@ -0,0 +1,13 @@
+//
+//  TabBarScrollableViewController.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 7/3/20.
+//  Copyright © 2020 Shadowfacts. All rights reserved.
+//
+
+import UIKit
+
+protocol TabBarScrollableViewController: UIViewController {
+    func tabBarScrollToTop()
+}