Trait FocusedTextFieldHandler 

pub trait FocusedTextFieldHandler {
    // Required methods
    fn handle_key(&self, event: &KeyEvent) -> bool;
    fn insert_text(&self, text: &str);
    fn delete_surrounding(&self, before_bytes: usize, after_bytes: usize);
    fn copy_selection(&self) -> Option<String>;
    fn cut_selection(&self) -> Option<String>;
    fn set_composition(&self, text: &str, cursor: Option<(usize, usize)>);

    // Provided methods
    fn select_all(&self) { ... }
    fn finish_composition(&self) { ... }
    fn set_composing_region(&self, start_bytes: usize, end_bytes: usize) { ... }
    fn set_selection(&self, start_bytes: usize, end_bytes: usize) { ... }
    fn editor_state(&self) -> Option<ImeEditorState> { ... }
}

Handler trait for focused text field operations. Stored in focus module for O(1) key/clipboard dispatch.

Required Methods

fn handle_key(&self, event: &KeyEvent) -> bool

Handle a key event. Returns true if consumed.

fn insert_text(&self, text: &str)

Insert pasted text.

fn delete_surrounding(&self, before_bytes: usize, after_bytes: usize)

Delete text surrounding the cursor or selection.

fn copy_selection(&self) -> Option<String>

Copy current selection. Returns None if nothing selected.

fn cut_selection(&self) -> Option<String>

Cut current selection (copy + delete). Returns None if nothing selected.

fn set_composition(&self, text: &str, cursor: Option<(usize, usize)>)

Set IME composition (preedit) state.

• text: The composition text being typed (empty string to clear, which deletes the preedit text)
• cursor: Optional cursor position within composition (start, end)

Provided Methods

fn select_all(&self)

Selects all the field’s text (contextual-menu “Select all”).

fn finish_composition(&self)

Finish the active composition, keeping the composed text as regular committed text (Android finishComposingText semantics). No-op when no composition is active.

fn set_composing_region(&self, start_bytes: usize, end_bytes: usize)

Mark existing text as the composing region without changing it (Android setComposingRegion semantics, used by autocorrect to re-compose an already committed word). Offsets are UTF-8 bytes; implementations clamp them to valid character boundaries.

fn set_selection(&self, start_bytes: usize, end_bytes: usize)

Move the selection/caret to [start_bytes, end_bytes) without editing text (Android InputConnection.setSelection semantics). Used by Gboard’s spacebar-swipe cursor control, which scrubs the caret by repeatedly setting the selection. Offsets are UTF-8 bytes; implementations clamp them to valid character boundaries.

fn editor_state(&self) -> Option<ImeEditorState>

Snapshot of the current editable state for platform IMEs (InputConnection text queries, session seeding). None when the handler cannot expose its state.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors