I have developed an IOS 8 custom keyboard. I want to give it "undo" and "redo" functionality, like the default system keyboard. I have tried it in different ways but was unable to find a good solution.
We can interact with a Text Input Object textDocumentProxy with the methods
insertText
deleteBackward
documentContextAfterInput
ocumentContextBeforeInput
But I was unable to find any way of implementing "undo" and "redo" functionality.
I think we can NOT implement these function (undo,redo)
According to https://developer.apple.com/library/ios/documentation/General/Conceptual/ExtensibilityPG/Keyboard.html
Because a custom keyboard can draw only within the primary view of its UIInputViewController object, it cannot select text. Text selection is under the control of the app that is using the keyboard. If that app provides an editing menu interface (such as for Cut, Copy, and Paste), the keyboard has no access to it. A custom keyboard cannot offer inline autocorrection controls near the insertion point.
I think there are many case that content of textfield changed and you can not know when it changed, how it changed. If we can not know, we can not know to undo to where too. I think so.
I'm developing Custom keyboard extension like you and I have many problems. (eg: how can we know the current cursor to get current text selection...)
My question: Current text selection in CustomKeyBoardExtension (hope somebody know)