From d72c26796dba87438d72b980e3c67bb8c90f5c61 Mon Sep 17 00:00:00 2001
From: Matthew Chen <matthew@signal.org>
Date: Tue, 5 Mar 2019 10:31:20 -0800
Subject: [PATCH] Ensure onboarding views never reclaim layout space from
 dismissed keyboard.

---
 .../Registration/OnboardingBaseViewController.swift         | 6 ++++++
 SignalMessaging/ViewControllers/OWSViewController.h         | 4 ++++
 SignalMessaging/ViewControllers/OWSViewController.m         | 6 +++++-
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/Signal/src/ViewControllers/Registration/OnboardingBaseViewController.swift b/Signal/src/ViewControllers/Registration/OnboardingBaseViewController.swift
index a1594d3ec..6d59d0f9e 100644
--- a/Signal/src/ViewControllers/Registration/OnboardingBaseViewController.swift
+++ b/Signal/src/ViewControllers/Registration/OnboardingBaseViewController.swift
@@ -73,6 +73,12 @@ public class OnboardingBaseViewController: OWSViewController {
 
     // MARK: - View Lifecycle
 
+    public override func viewDidLoad() {
+        super.viewDidLoad()
+
+        self.shouldBottomViewReserveSpaceForKeyboard = true
+    }
+
     public override func viewWillAppear(_ animated: Bool) {
         super.viewWillAppear(animated)
 
diff --git a/SignalMessaging/ViewControllers/OWSViewController.h b/SignalMessaging/ViewControllers/OWSViewController.h
index 6e0ed2c3c..71cb28ad2 100644
--- a/SignalMessaging/ViewControllers/OWSViewController.h
+++ b/SignalMessaging/ViewControllers/OWSViewController.h
@@ -20,6 +20,10 @@ UIInterfaceOrientationMask DefaultUIInterfaceOrientationMask(void);
 // BUT adjust its location upward if the keyboard appears.
 - (void)autoPinViewToBottomOfViewControllerOrKeyboard:(UIView *)view avoidNotch:(BOOL)avoidNotch;
 
+// If YES, the bottom view never "reclaims" layout space if the keyboard is dismissed.
+// Defaults to NO.
+@property (nonatomic) BOOL shouldBottomViewReserveSpaceForKeyboard;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/SignalMessaging/ViewControllers/OWSViewController.m b/SignalMessaging/ViewControllers/OWSViewController.m
index 31350bd91..5d756ee94 100644
--- a/SignalMessaging/ViewControllers/OWSViewController.m
+++ b/SignalMessaging/ViewControllers/OWSViewController.m
@@ -211,7 +211,11 @@ UIInterfaceOrientationMask DefaultUIInterfaceOrientationMask(void)
         // There's no need to use: [UIView animateWithDuration:...].
         // Any layout changes made during these notifications are
         // automatically animated.
-        self.bottomLayoutConstraint.constant = offset;
+        if (self.shouldBottomViewReserveSpaceForKeyboard) {
+            self.bottomLayoutConstraint.constant = MIN(self.bottomLayoutConstraint.constant, offset);
+        } else {
+            self.bottomLayoutConstraint.constant = offset;
+        }
         [self.bottomLayoutView.superview layoutIfNeeded];
     };