Inputbar incorrect position after keyboard appear on iPad presented as formsheet

[lingzlu]

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• [x] I've searched for any related issues and avoided creating a duplicate issue.

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:

• [x] 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 https://github.com/slackhq/SlackTextViewController/blob/37f91f23414dda33db5ce43a20958f19ddbd7b1d/Source/SLKTextViewController.m#L405-L423 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 https://github.com/slackhq/SlackTextViewController/blob/37f91f23414dda33db5ce43a20958f19ddbd7b1d/Source/SLKTextViewController.m#L1407-L1409 from slk_willShowOrHideKeyboard to slk_didShowOrHideKeyboard. But then it loses smooth transition on input bar moving up with keyboard. Any suggestions?