Add fast account switching indicator to tab bar item

Tusker.xcodeproj/project.pbxproj

@@ -186,6 +186,7 @@
 		D67895C0246870DE00D4CD9E /* LocalAccountAvatarView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D67895BF246870DE00D4CD9E /* LocalAccountAvatarView.swift */; };
 		D679C09F215850EF00DA27FE /* XCBActions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D679C09E215850EF00DA27FE /* XCBActions.swift */; };
 		D67B506D250B291200FAECFB /* BlurHashDecode.swift in Sources */ = {isa = PBXBuildFile; fileRef = D67B506C250B291200FAECFB /* BlurHashDecode.swift */; };
+		D67C1795266D57D10070F250 /* FastAccountSwitcherIndicatorView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D67C1794266D57D10070F250 /* FastAccountSwitcherIndicatorView.swift */; };
 		D67C57AD21E265FC00C3118B /* LargeAccountDetailView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D67C57AC21E265FC00C3118B /* LargeAccountDetailView.swift */; };
 		D67C57AF21E28EAD00C3118B /* Array+Uniques.swift in Sources */ = {isa = PBXBuildFile; fileRef = D67C57AE21E28EAD00C3118B /* Array+Uniques.swift */; };
 		D68015402401A6BA00D6103B /* ComposingPrefsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D680153F2401A6BA00D6103B /* ComposingPrefsView.swift */; };
@@ -587,6 +588,7 @@
 		D67895BF246870DE00D4CD9E /* LocalAccountAvatarView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalAccountAvatarView.swift; sourceTree = "<group>"; };
 		D679C09E215850EF00DA27FE /* XCBActions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XCBActions.swift; sourceTree = "<group>"; };
 		D67B506C250B291200FAECFB /* BlurHashDecode.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BlurHashDecode.swift; sourceTree = "<group>"; };
+		D67C1794266D57D10070F250 /* FastAccountSwitcherIndicatorView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FastAccountSwitcherIndicatorView.swift; sourceTree = "<group>"; };
 		D67C57AC21E265FC00C3118B /* LargeAccountDetailView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LargeAccountDetailView.swift; sourceTree = "<group>"; };
 		D67C57AE21E28EAD00C3118B /* Array+Uniques.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Array+Uniques.swift"; sourceTree = "<group>"; };
 		D680153F2401A6BA00D6103B /* ComposingPrefsView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ComposingPrefsView.swift; sourceTree = "<group>"; };
@@ -1449,6 +1451,7 @@
 				D6B4A4FE2506B81A000C81C1 /* AccountDisplayNameLabel.swift */,
 				D6E426B225337C7000C02E1C /* CustomEmojiImageView.swift */,
 				D6EAE0DA2550CC8A002DB0AC /* FocusableTextField.swift */,
+				D67C1794266D57D10070F250 /* FastAccountSwitcherIndicatorView.swift */,
 				D67C57A721E2649B00C3118B /* Account Detail */,
 				D626494023C122C800612E6E /* Asset Picker */,
 				D61959D0241E842400A37B8E /* Draft Cell */,
@@ -2168,6 +2171,7 @@
 				D6AEBB432321685E00E5038B /* OpenInSafariActivity.swift in Sources */,
 				D6C693FE2162FEEA007D6A6D /* UIViewController+Children.swift in Sources */,
 				D64D0AB12128D9AE005A6F37 /* OnboardingViewController.swift in Sources */,
+				D67C1795266D57D10070F250 /* FastAccountSwitcherIndicatorView.swift in Sources */,
 				D627FF76217E923E00CC0648 /* DraftsManager.swift in Sources */,
 				D64F80E2215875CC00BEF393 /* XCBActionType.swift in Sources */,
 				04586B4322B301470021BD04 /* AppearancePrefsView.swift in Sources */,

Tusker/Screens/Main/MainTabBarViewController.swift

@@ -15,6 +15,9 @@ class MainTabBarViewController: UITabBarController, UITabBarControllerDelegate {
     private var composePlaceholder: UIViewController!
     private var fastAccountSwitcher: FastAccountSwitcherViewController!
     
+    private var fastSwitcherIndicator: FastAccountSwitcherIndicatorView!
+    private var fastSwitcherConstraints: [NSLayoutConstraint] = []
+    
     var selectedTab: Tab {
         return Tab(rawValue: selectedIndex)!
     }
@@ -70,9 +73,62 @@ class MainTabBarViewController: UITabBarController, UITabBarControllerDelegate {
         tapRecognizer.cancelsTouchesInView = false
         tabBar.addGestureRecognizer(tapRecognizer)
         
+        if findMyProfileTabBarButton() != nil {
+            fastSwitcherIndicator = FastAccountSwitcherIndicatorView()
+            fastSwitcherIndicator.translatesAutoresizingMaskIntoConstraints = false
+            view.addSubview(fastSwitcherIndicator)
+            NSLayoutConstraint.activate([
+                fastSwitcherIndicator.widthAnchor.constraint(equalToConstant: 10),
+                fastSwitcherIndicator.heightAnchor.constraint(equalToConstant: 12),
+            ])
+        }
+        
         tabBar.isSpringLoaded = true
     }
     
+    override func viewWillAppear(_ animated: Bool) {
+        super.viewWillAppear(animated)
+        
+        repositionFastSwitcherIndicator()
+    }
+    
+    override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
+        super.traitCollectionDidChange(previousTraitCollection)
+        
+        repositionFastSwitcherIndicator()
+    }
+    
+    private func repositionFastSwitcherIndicator() {
+        guard let myProfileButton = findMyProfileTabBarButton() else {
+            return
+        }
+        NSLayoutConstraint.deactivate(fastSwitcherConstraints)
+        // using interfaceOrientation isn't ideal, but UITabBar buttons may lay out horizontally even in the compact size class
+        if traitCollection.horizontalSizeClass == .compact && interfaceOrientation.isPortrait {
+            fastSwitcherConstraints = [
+                fastSwitcherIndicator.centerYAnchor.constraint(equalTo: myProfileButton.centerYAnchor, constant: -4),
+                // tab bar button image width is 30
+                fastSwitcherIndicator.leftAnchor.constraint(equalTo: myProfileButton.centerXAnchor, constant: 15 + 2),
+            ]
+        } else {
+            fastSwitcherConstraints = [
+                fastSwitcherIndicator.centerYAnchor.constraint(equalTo: myProfileButton.centerYAnchor),
+                fastSwitcherIndicator.trailingAnchor.constraint(equalTo: myProfileButton.trailingAnchor),
+            ]
+        }
+        NSLayoutConstraint.activate(fastSwitcherConstraints)
+    }
+    
+    private func findMyProfileTabBarButton() -> UIView? {
+        let tabBarButtons = tabBar.subviews.filter { String(describing: type(of: $0)).lowercased().contains("button") }
+        // sanity check that there is 1 button per VC
+        guard tabBarButtons.count == viewControllers!.count,
+              let myProfileButton = tabBarButtons.last else {
+            return nil
+        }
+        return myProfileButton
+    }
+    
     @objc private func tabBarTapped(_ recognizer: UITapGestureRecognizer) {
         fastAccountSwitcher.hide()
     }
@@ -146,13 +202,9 @@ extension MainTabBarViewController {
 
 extension MainTabBarViewController: FastAccountSwitcherViewControllerDelegate {
     func fastAccountSwitcher(_ fastAccountSwitcher: FastAccountSwitcherViewController, triggerZoneContains point: CGPoint) -> Bool {
-        let tabBarButtons = tabBar.subviews.filter { String(describing: type(of: $0)).lowercased().contains("button") }
+        guard let myProfileButton = findMyProfileTabBarButton() else {
-        // sanity check that there is 1 button per VC
-        guard tabBarButtons.count == viewControllers!.count,
-              let myProfileButton = tabBarButtons.last else {
             return false
         }
-        
         let locationInButton = myProfileButton.convert(point, from: fastAccountSwitcher.view)
         return myProfileButton.bounds.contains(locationInButton)
     }

Tusker/Views/FastAccountSwitcherIndicatorView.swift

@@ -0,0 +1,30 @@
+//
+//  FastAccountSwitchingIndicatorView.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 6/6/21.
+//  Copyright © 2021 Shadowfacts. All rights reserved.
+//
+
+import UIKit
+
+class FastAccountSwitcherIndicatorView: UIView {
+    
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        
+        tintColor = .lightGray
+        
+        let up = UIImageView(image: UIImage(systemName: "arrowtriangle.up.fill")!)
+        up.frame = CGRect(x: 0, y: 0, width: 10, height: 5)
+        addSubview(up)
+        let down = UIImageView(image: UIImage(systemName: "arrowtriangle.down.fill")!)
+        down.frame = CGRect(x: 0, y: 7, width: 10, height: 5)
+        addSubview(down)
+    }
+    
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+}