Merge pull request slackhq#542 from slackhq/keyboardHeightScroll

Correct content offset for keyboard when uninverted

Author: ZAndyL

Source/SLKTextViewController.m

@@ -1380,6 +1380,8 @@ - (void)slk_willShowOrHideKeyboard:(NSNotification *)notification
         [self slk_hideAutoCompletionViewIfNeeded];
     }
 
+    UIScrollView *scrollView = self.scrollViewProxy;
+    
     NSInteger curve = [notification.userInfo[UIKeyboardAnimationCurveUserInfoKey] integerValue];
     NSTimeInterval duration = [notification.userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
 
@@ -1390,10 +1392,10 @@ - (void)slk_willShowOrHideKeyboard:(NSNotification *)notification
         // Scrolls to bottom only if the keyboard is about to show.
         if (self.shouldScrollToBottomAfterKeyboardShows && self.keyboardStatus == SLKKeyboardStatusWillShow) {
             if (self.isInverted) {
-                [self.scrollViewProxy slk_scrollToTopAnimated:YES];
+                [scrollView slk_scrollToTopAnimated:YES];
             }
             else {
-                [self.scrollViewProxy slk_scrollToBottomAnimated:YES];
+                [scrollView slk_scrollToBottomAnimated:YES];
             }
         }
     };
@@ -1403,6 +1405,20 @@ - (void)slk_willShowOrHideKeyboard:(NSNotification *)notification
     // Second condition: check if the height of the keyboard changed.
     if (!CGRectEqualToRect(beginFrame, endFrame) || fabs(previousKeyboardHeight - self.keyboardHC.constant) > 0.0)
     {
+        // Content Offset correction if not inverted and not auto-completing.
+        if (!self.isInverted && !self.isAutoCompleting) {
+            
+            CGFloat scrollViewHeight = self.scrollViewHC.constant;
+            CGFloat keyboardHeight = self.keyboardHC.constant;
+            CGSize contentSize = scrollView.contentSize;
+            CGPoint contentOffset = scrollView.contentOffset;
+            
+            CGFloat newOffset = MIN(contentSize.height - scrollViewHeight,
+                                    contentOffset.y + keyboardHeight - previousKeyboardHeight);
+            
+            scrollView.contentOffset = CGPointMake(contentOffset.x, newOffset);
+        }
+        
         // Only for this animation, we set bo to bounce since we want to give the impression that the text input is glued to the keyboard.
         [self.view slk_animateLayoutIfNeededWithDuration:duration
                                                   bounce:NO