# Text Input ## How are key events sent from the keyboard? * `SystemChannels.keyEvent` exposes a messaging channel that receives raw key data whenever the platform produces keyboard events. * `RawKeyboard` subscribes to this channel and forwards incoming messages as `RawKeyEvent` instances (which encapsulate `RawKeyEventData`). Physical and logical interpretations of the event are exposed via `RawKeyEvent.physicalKey` and `RawKeyEvent.logicalKey`, respectively. The character produced is available as `RawKeyEvent.character` but only for `RawKeyDownEvent` events. This field accounts for modifier keys / past keystrokes producing null for invalid combinations or a dart string, otherwise. * The physical key identifies the actual position of the key that was struck, expressed as the equivalent key on a standard `QWERTY` keyboard. The logical key ignores position, taking into account any mappings or layout changes to produce the actual key the user intended. * Subclasses of `RawKeyEventData` interpret platform-specific data to categorize the keystroke in a portable way (`RawKeyEventDataAndroid`, `RawKeyEventDataMacOs`) ## What is an `IME`? * `IME` stands for “input method editor,” which corresponds to any sort of on-screen text editing interface, such as the software keyboard. There can only be one active `IME` at a time. ## How does `Flutter` interact with `IMEs`? * `SystemChannels.textInput` exposes a method channel that implements a transactional interface for interacting with an `IME`. Operations are scoped to a given transaction (client), which is implicit once created. Outbound methods support configuring the `IME`, showing/hiding UI, and update editing state (including selections); inbound methods handle `IME` actions and editing changes. Convenient wrappers for this protocol make much of this seamless. ## What are the building blocks for interacting with an `IME`? * `TextInput.attach` federates access to the `IME`, setting the current client (transaction) that can interact with the keyboard. * `TextInputClient` is an interface to receive information from the `IME`. Once attached, clients are notified via method invocation when actions are invoked, the editing value is updated, or the cursor is moved. * `TextInputConnection` is returned by `TextInput.attach` and allows the `IME` to be altered. In particular, the editing state can be changed, the `IME` shown, and the connection closed. Once closed, if no other client attaches within the current animation frame, the `IME` will also be hidden. * `TextInputConfiguration` encapsulates configuration data sent to the `IME` when a client attaches. This includes the desired input type (e.g., “datetime”, “`emailAddress`”, “phone”) for which to optimize the `IME`, whether to enable autocorrect, whether to obscure input, the default action, capitalization mode (`TextCapitalization`), and more. * `TextInputAction` enumerates the set of special actions supported on all platforms (e.g., “`emergencyCall`”, “done”, “next”). Actions may only be used on platforms that support them. Actions have no intrinsic meaning; developers determine how to respond to actions themselves. * `TextEditingValue` represents the current text, selection, and composing state (range being edited) for a run of text. * `RawFloatingCursorPoint` represents the position of the “floating cursor” on `iOS`, a special cursor that appears when the user force presses the keyboard. Its position is reported via the client, including state changes (`RawFloatingCursorDragState`). --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://flutter.megathink.com/text/text-input.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.