Further improve "first responder" behavior in the image editor.

SignalMessaging/ViewControllers/AttachmentApproval/AttachmentApprovalInputAccessoryView.swift

@@ -101,11 +101,7 @@ class AttachmentApprovalInputAccessoryView: UIView {
 
     // MARK: 
 
-    public var shouldHideControls = false {
-        didSet {
-            updateContents()
-        }
-    }
+    private var shouldHideControls = false
 
     private func updateContents() {
         var hasCurrentCaption = false
@@ -135,6 +131,10 @@ class AttachmentApprovalInputAccessoryView: UIView {
             if !attachmentCaptionToolbar.textView.isFirstResponder {
                 attachmentCaptionToolbar.textView.becomeFirstResponder()
             }
+        } else {
+            if attachmentCaptionToolbar.textView.isFirstResponder {
+                attachmentCaptionToolbar.textView.resignFirstResponder()
+            }
         }
         // NOTE: We don't automatically make attachmentTextToolbar.textView
         // first responder;
@@ -143,9 +143,18 @@ class AttachmentApprovalInputAccessoryView: UIView {
     }
 
     public func update(isEditingCaptions: Bool,
-                       currentAttachmentItem: SignalAttachmentItem?) {
+                       currentAttachmentItem: SignalAttachmentItem?,
+                       shouldHideControls: Bool) {
+        // De-bounce
+        guard self.isEditingCaptions != isEditingCaptions ||
+            self.currentAttachmentItem != currentAttachmentItem ||
+            self.shouldHideControls != shouldHideControls else {
+            return
+        }
+
         self.isEditingCaptions = isEditingCaptions
         self.currentAttachmentItem = currentAttachmentItem
+        self.shouldHideControls = shouldHideControls
 
         updateContents()
     }

SignalMessaging/ViewControllers/AttachmentApproval/AttachmentApprovalViewController.swift

@@ -184,7 +184,6 @@ public class AttachmentApprovalViewController: UIPageViewController, UIPageViewC
     private func updateContents() {
         updateNavigationBar()
         updateInputAccessory()
-        updateControlVisibility()
 
         touchInterceptorView.isHidden = !isEditingCaptions
     }
@@ -206,7 +205,10 @@ public class AttachmentApprovalViewController: UIPageViewController, UIPageViewC
             currentPageViewController = pageViewControllers.first
         }
         let currentAttachmentItem: SignalAttachmentItem? = currentPageViewController?.attachmentItem
-        bottomToolView.update(isEditingCaptions: isEditingCaptions, currentAttachmentItem: currentAttachmentItem)
+
+        bottomToolView.update(isEditingCaptions: isEditingCaptions,
+                              currentAttachmentItem: currentAttachmentItem,
+                              shouldHideControls: shouldHideControls)
     }
 
     // MARK: - Navigation Bar
@@ -327,15 +329,6 @@ public class AttachmentApprovalViewController: UIPageViewController, UIPageViewC
         return pageViewController.shouldHideControls
     }
 
-    private func updateControlVisibility() {
-        let hasPresentedView = self.presentedViewController != nil
-
-        if !shouldHideControls, !isFirstResponder, !hasPresentedView {
-            becomeFirstResponder()
-        }
-        bottomToolView.shouldHideControls = shouldHideControls
-    }
-
     // MARK: - View Helpers
 
     func remove(attachmentItem: SignalAttachmentItem) {
@@ -411,8 +404,6 @@ public class AttachmentApprovalViewController: UIPageViewController, UIPageViewC
                 updateMediaRail()
             }
         }
-
-        updateContents()
     }
 
     // MARK: - UIPageViewControllerDataSource
@@ -463,6 +454,18 @@ public class AttachmentApprovalViewController: UIPageViewController, UIPageViewC
         return super.viewControllers!.map { $0 as! AttachmentPrepViewController }
     }
 
+    @objc
+    public override func setViewControllers(_ viewControllers: [UIViewController]?, direction: UIPageViewController.NavigationDirection, animated: Bool, completion: ((Bool) -> Void)? = nil) {
+        super.setViewControllers(viewControllers,
+                                 direction: direction,
+                                 animated: animated) { [weak self] (finished) in
+                                    if let completion = completion {
+                                        completion(finished)
+                                    }
+                                    self?.updateContents()
+        }
+    }
+
     var currentItem: SignalAttachmentItem! {
         get {
             return currentPageViewController.attachmentItem
@@ -682,7 +685,7 @@ extension AttachmentApprovalViewController: AttachmentPrepViewControllerDelegate
     }
 
     func prepViewControllerUpdateControls() {
-        updateControlVisibility()
+        updateInputAccessory()
     }
 }