On What's New in iOS11 page, I found that 'Added needsInputModeSwitchKey, a property of UIInputViewController to control the display of the input-mode switch key'.The new property needsInputModeSwitchKey is readonly. I have developed a keyboard Extension via Swift, but I have no idea about this new property. Can someone give some advice. Thank you!.
I've resolved it by myself. While all input mothod is removed except a 3rd. There will be only one input method can be switched to. In this situation，the needsInputModeSwitchKey is false, and the switch key should be hide from 3rd keyboard extension.