Inputbar incorrect position after keyboard appear on iPad presented as formsheet

[lingzlu]

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Description

When present SLKTextViewController on iPad in formsheet style. Input bar position was not computed correctly when keyboard appears. Portrait orientation does not repro the issue.

Reproducible in:

• This is reproducible in the sample project.
  SlackTextViewController version: 1.9.6
  iOS version(s): iOS 11
  Device(s): iPad Air 2

Steps to reproduce:

1. Run the sample app "Messenger-iPad-sheet" on iPad
2. Change device orientation on landscape
3. Invoke keyboard on the input bar by using one of navigation bar actions.

Expected result:

Input bar should be stick on top of keyboard.

Actual result:

There is an empty gap between the input bar and the keyboard.

Attachments:

Investigation

Briefly look at the source code, I suspect the problem is in

SlackTextViewController/Source/SLKTextViewController.m

Lines 405 to 423 in 37f91f2

	- (CGFloat)slk_appropriateKeyboardHeightFromRect:(CGRect)rect
	{
	CGRect keyboardRect = [self.view convertRect:rect fromView:nil];
	CGFloat viewHeight = CGRectGetHeight(self.view.bounds);
	CGFloat keyboardMinY = CGRectGetMinY(keyboardRect);
	CGFloat keyboardHeight = MAX(0.0, viewHeight - keyboardMinY);
	CGFloat bottomMargin = [self slk_appropriateBottomMargin];
	// When the keyboard height is zero, we can assume there is no keyboard visible
	// In that case, let's see if there are any other views outside of the view hiearchy
	// requiring to adjust the text input bottom margin
	if (keyboardHeight < bottomMargin) {
	keyboardHeight = bottomMargin;
	}
	return keyboardHeight;
	}

When keyboard appeared on landscape, the formsheet is been pushed up. ConvertRect will return the keyboardRect on origin view frame, result in incorrect keyboardHeight been computed. I tried to fix the issue by moving

SlackTextViewController/Source/SLKTextViewController.m

Lines 1407 to 1409 in 37f91f2

	// Updates the height constraints' constants
	self.keyboardHC.constant = [self slk_appropriateKeyboardHeightFromNotification:notification];
	self.scrollViewHC.constant = [self slk_appropriateScrollViewHeight];

from slk_willShowOrHideKeyboard to slk_didShowOrHideKeyboard. But then it loses smooth transition on input bar moving up with keyboard. Any suggestions?