maintain body text navigating to/from approval view

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -2858,7 +2858,8 @@ typedef enum : NSUInteger {
             UIViewController *pickerModal;
 
             if (SSKFeatureFlags.useCustomPhotoCapture) {
-                SendMediaNavigationController *navController = [SendMediaNavigationController showingCameraFirst];
+                SendMediaNavigationController *navController =
+                    [SendMediaNavigationController showingCameraFirstWithMessageText:self.inputToolbar.messageText];
                 navController.sendMediaNavDelegate = self;
                 pickerModal = navController;
             } else {
@@ -2903,7 +2904,8 @@ typedef enum : NSUInteger {
             return;
         }
 
-        SendMediaNavigationController *pickerModal = [SendMediaNavigationController showingMediaLibraryFirst];
+        SendMediaNavigationController *pickerModal =
+            [SendMediaNavigationController showingMediaLibraryFirstWithMessageText:self.inputToolbar.messageText];
         pickerModal.sendMediaNavDelegate = self;
 
         [self dismissKeyBoard];
@@ -3921,6 +3923,14 @@ typedef enum : NSUInteger {
     [self dismissViewControllerAnimated:YES completion:nil];
 }
 
+- (void)attachmentApproval:(AttachmentApprovalViewController *)attachmentApproval
+      didChangeMessageText:(nullable NSString *)newMessageText
+{
+    [self.inputToolbar setMessageText:newMessageText animated:NO];
+}
+
+#pragma mark -
+
 - (void)showErrorAlertForAttachment:(SignalAttachment *_Nullable)attachment
 {
     OWSAssertDebug(attachment == nil || [attachment hasError]);

Signal/src/ViewControllers/Photos/SendMediaNavigationController.swift

@@ -19,6 +19,8 @@ class SendMediaNavigationController: OWSNavigationController {
 
     override var prefersStatusBarHidden: Bool { return true }
 
+    var messageText: String?
+
     override func viewDidLoad() {
         super.viewDidLoad()
 
@@ -51,19 +53,21 @@ class SendMediaNavigationController: OWSNavigationController {
     public weak var sendMediaNavDelegate: SendMediaNavDelegate?
 
     @objc
-    public class func showingCameraFirst() -> SendMediaNavigationController {
+    public class func showingCameraFirst(messageText: String) -> SendMediaNavigationController {
         let navController = SendMediaNavigationController()
         navController.setViewControllers([navController.captureViewController], animated: false)
         navController.updateButtons()
+        navController.messageText = messageText
 
         return navController
     }
 
     @objc
-    public class func showingMediaLibraryFirst() -> SendMediaNavigationController {
+    public class func showingMediaLibraryFirst(messageText: String) -> SendMediaNavigationController {
         let navController = SendMediaNavigationController()
         navController.setViewControllers([navController.mediaLibraryViewController], animated: false)
         navController.updateButtons()
+        navController.messageText = messageText
 
         return navController
     }
@@ -210,6 +214,7 @@ class SendMediaNavigationController: OWSNavigationController {
     private func pushApprovalViewController() {
         let approvalViewController = AttachmentApprovalViewController(mode: .sharedNavigation, attachments: self.attachments)
         approvalViewController.approvalDelegate = self
+        approvalViewController.messageText = messageText
 
         pushViewController(approvalViewController, animated: true)
         updateButtons()
@@ -361,6 +366,10 @@ extension SendMediaNavigationController: ImagePickerGridControllerDelegate {
 }
 
 extension SendMediaNavigationController: AttachmentApprovalViewControllerDelegate {
+    func attachmentApproval(_ attachmentApproval: AttachmentApprovalViewController, didChangeMessageText newMessageText: String?) {
+        self.messageText = newMessageText
+    }
+
     func attachmentApproval(_ attachmentApproval: AttachmentApprovalViewController, didRemoveAttachment attachment: SignalAttachment) {
         guard let removedDraft = attachmentDraftCollection.attachmentDrafts.first(where: { $0.attachment == attachment}) else {
             owsFailDebug("removedDraft was unexpectedly nil")

SignalMessaging/ViewControllers/AttachmentApproval/AttachmentApprovalViewController.swift

@@ -9,17 +9,19 @@ import PromiseKit
 
 @objc
 public protocol AttachmentApprovalViewControllerDelegate: class {
-    func attachmentApproval(_ attachmentApproval: AttachmentApprovalViewController, didApproveAttachments attachments: [SignalAttachment], messageText: String?)
+    func attachmentApproval(_ attachmentApproval: AttachmentApprovalViewController,
+                            didApproveAttachments attachments: [SignalAttachment], messageText: String?)
+
     func attachmentApprovalDidCancel(_ attachmentApproval: AttachmentApprovalViewController)
 
+    func attachmentApproval(_ attachmentApproval: AttachmentApprovalViewController,
+                            didChangeMessageText newMessageText: String?)
+
     @objc
     optional func attachmentApproval(_ attachmentApproval: AttachmentApprovalViewController, didRemoveAttachment attachment: SignalAttachment)
 
     @objc
     optional func attachmentApprovalDidTapAddMore(_ attachmentApproval: AttachmentApprovalViewController)
-
-    @objc
-    optional func attachmentApproval(_ attachmentApproval: AttachmentApprovalViewController, changedCaptionOfAttachment attachment: SignalAttachment)
 }
 
 // MARK: -
@@ -216,6 +218,15 @@ public class AttachmentApprovalViewController: UIPageViewController, UIPageViewC
         bottomToolView.update(isEditingCaptions: isEditingCaptions, currentAttachmentItem: currentAttachmentItem)
     }
 
+    public var messageText: String? {
+        get {
+            return attachmentTextToolbar.messageText
+        }
+        set {
+            attachmentTextToolbar.messageText = newValue
+        }
+    }
+
     // MARK: - Navigation Bar
 
     public func updateNavigationBar() {
@@ -678,6 +689,10 @@ extension AttachmentApprovalViewController: AttachmentTextToolbarDelegate {
     func attachmentTextToolbarDidAddMore(_ attachmentTextToolbar: AttachmentTextToolbar) {
         self.approvalDelegate?.attachmentApprovalDidTapAddMore?(self)
     }
+
+    func attachmentTextToolbarDidChange(_ attachmentTextToolbar: AttachmentTextToolbar) {
+        approvalDelegate?.attachmentApproval(self, didChangeMessageText: attachmentTextToolbar.messageText)
+    }
 }
 
 // MARK: -

SignalMessaging/ViewControllers/AttachmentApproval/AttachmentTextToolbar.swift

@@ -13,6 +13,7 @@ protocol AttachmentTextToolbarDelegate: class {
     func attachmentTextToolbarDidBeginEditing(_ attachmentTextToolbar: AttachmentTextToolbar)
     func attachmentTextToolbarDidEndEditing(_ attachmentTextToolbar: AttachmentTextToolbar)
     func attachmentTextToolbarDidAddMore(_ attachmentTextToolbar: AttachmentTextToolbar)
+    func attachmentTextToolbarDidChange(_ attachmentTextToolbar: AttachmentTextToolbar)
 }
 
 // MARK: -
@@ -228,6 +229,7 @@ class AttachmentTextToolbar: UIView, UITextViewDelegate {
 
     public func textViewDidChange(_ textView: UITextView) {
         updateHeight(textView: textView)
+        attachmentTextToolbarDelegate?.attachmentTextToolbarDidChange(self)
     }
 
     public func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {

SignalMessaging/ViewControllers/SharingThreadPickerViewController.m

@@ -310,6 +310,12 @@ typedef void (^SendMessageBlock)(SendCompletionBlock completion);
     [self cancelShareExperience];
 }
 
+- (void)attachmentApproval:(AttachmentApprovalViewController *)attachmentApproval
+      didChangeMessageText:(nullable NSString *)newMessageText
+{
+    // no-op
+}
+
 #pragma mark - MessageApprovalViewControllerDelegate
 
 - (void)messageApproval:(MessageApprovalViewController *)approvalViewController