# UIInputViewController The primary view controller for a custom keyboard app extension. ``` @MainActor class UIInputViewController ``` ## Overview To create a custom keyboard, first subclass the [`UIInputViewController`](/documentation/UIKit/UIInputViewController) class, then add your keyboard’s user interface to the [`inputView`](/documentation/UIKit/UIInputViewController/inputView) property of your subclass. In Xcode, you can start a custom keyboard by choosing the Custom Keyboard target template. A custom keyboard can respond to user input events in the following ways: - Add text in the form of an unattributed object at the insertion point in the current text input object, by calling the [`insertText(_:)`](/documentation/UIKit/UIKeyInput/insertText(_:)) method on the [`textDocumentProxy`](/documentation/UIKit/UIInputViewController/textDocumentProxy) property. This property provides that method through its conformance to the [`UIKeyInput`](/documentation/UIKit/UIKeyInput) protocol - Delete text in a backward direction, starting at the insertion point, by calling the [`deleteBackward()`](/documentation/UIKit/UIKeyInput/deleteBackward()) method on the [`textDocumentProxy`](/documentation/UIKit/UIInputViewController/textDocumentProxy) property. - Switch to another keyboard in the set of user-enabled keyboards, by calling the [`advanceToNextInputMode()`](/documentation/UIKit/UIInputViewController/advanceToNextInputMode()) method. - Dismiss the keyboard, by calling the [`dismissKeyboard()`](/documentation/UIKit/UIInputViewController/dismissKeyboard()) method. Obtain textual context around the insertion point by reading the [`textDocumentProxy`](/documentation/UIKit/UIInputViewController/textDocumentProxy) properties [`documentContextBeforeInput`](/documentation/UIKit/UITextDocumentProxy/documentContextBeforeInput) and [`documentContextAfterInput`](/documentation/UIKit/UITextDocumentProxy/documentContextAfterInput). To find out if the current text input object is empty, call the [`hasText`](/documentation/UIKit/UIKeyInput/hasText) method on the [`textDocumentProxy`](/documentation/UIKit/UIInputViewController/textDocumentProxy) property. You can employ this textual context by considering it along with user input, to offer context-sensitive output to a document from your keyboard. An input view controller conforms to the [`UITextInputDelegate`](/documentation/UIKit/UITextInputDelegate) protocol, allowing you to respond to changes in document content and position of the insertion point. To present an appropriate keyboard layout, respond to the current text input object’s [`UIKeyboardType`](/documentation/UIKit/UIKeyboardType) property. For each keyboard type trait you support, change the contents of your primary view accordingly. For more about creating a custom keyboard, read [Custom Keyboard](https://developer.apple.com/library/archive/documentation/General/Conceptual/ExtensibilityPG/CustomKeyboard.html#//apple_ref/doc/uid/TP40014214-CH16) in [App Extension Programming Guide](https://developer.apple.com/library/archive/documentation/General/Conceptual/ExtensibilityPG/index.html#//apple_ref/doc/uid/TP40014214). ## Topics ### Providing a user interface for a custom keyboard [`inputView`](/documentation/UIKit/UIInputViewController/inputView) The primary view for the input view controller. ### Controlling a custom keyboard [`advanceToNextInputMode()`](/documentation/UIKit/UIInputViewController/advanceToNextInputMode()) Switches to the next keyboard in the list of user-enabled keyboards. [`dismissKeyboard()`](/documentation/UIKit/UIInputViewController/dismissKeyboard()) Dismisses the custom keyboard from the screen. [`handleInputModeList(from:with:)`](/documentation/UIKit/UIInputViewController/handleInputModeList(from:with:)) Supports interaction with the list of user-enabled keyboards. ### Interacting with a text input object [`textDocumentProxy`](/documentation/UIKit/UIInputViewController/textDocumentProxy) A proxy to the text input object that the custom keyboard is interacting with. [`UITextDocumentProxy`](/documentation/UIKit/UITextDocumentProxy) An object that provides textual context to a custom keyboard. ### Obtaining a supplementary lexicon [`requestSupplementaryLexicon(completion:)`](/documentation/UIKit/UIInputViewController/requestSupplementaryLexicon(completion:)) Obtains a supplementary lexicon of term pairs in a custom keyboard. ### Changing the primary language of a custom keyboard [`primaryLanguage`](/documentation/UIKit/UIInputViewController/primaryLanguage) The primary language for a custom keyboard. ### Configuring the keyboard behaviors [`needsInputModeSwitchKey`](/documentation/UIKit/UIInputViewController/needsInputModeSwitchKey) A Boolean value that indicates whether the keyboard must display an input switcher key. [`hasFullAccess`](/documentation/UIKit/UIInputViewController/hasFullAccess) A Boolean value that indicates whether the keyboard has full access. [`hasDictationKey`](/documentation/UIKit/UIInputViewController/hasDictationKey) A Boolean value that indicates whether the keyboard has a dictation key. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)