Android APIs
Added in API level 3
package

android.view.inputmethod

Framework classes for interaction between views and input methods (such as soft keyboards). See InputMethodManager for an overview. In most cases the main classes here are not needed for most applications, since they are dealt with for you by TextView. When implementing a custom text editor, however, you will need to implement the InputConnection class to allow the current input method to interact with your view.

Interfaces

InputConnection The InputConnection interface is the communication channel from an InputMethod back to the application that is receiving its input. 
InputMethod The InputMethod interface represents an input method which can generate key events and text, such as digital, email addresses, CJK characters, other language characters, and etc., while handling various input events, and send the text back to the application that requests text input. 
InputMethod.SessionCallback  
InputMethodSession The InputMethodSession interface provides the per-client functionality of InputMethod that is safe to expose to applications. 
InputMethodSession.EventCallback  

Classes

BaseInputConnection Base class for implementors of the InputConnection interface, taking care of most of the common behavior for providing a connection to an Editable. 
CompletionInfo Information about a single text completion that an editor has reported to an input method. 
CorrectionInfo Information about a single text correction that an editor has reported to an input method. 
CursorAnchorInfo Positional information about the text insertion point and characters in the composition string. 
CursorAnchorInfo.Builder Builder for CursorAnchorInfo. 
EditorInfo An EditorInfo describes several attributes of a text editing object that an input method is communicating with (typically an EditText), most importantly the type of text content it contains and the current cursor position. 
ExtractedText Information about text that has been extracted for use by an input method. 
ExtractedTextRequest Description of what an input method would like from an application when extract text from its input editor. 
InputBinding Information given to an InputMethod about a client connecting to it. 
InputConnectionWrapper

Wrapper class for proxying calls to another InputConnection. 

InputMethodInfo This class is used to specify meta information of an input method. 
InputMethodManager Central system API to the overall input method framework (IMF) architecture, which arbitrates interaction between applications and the current input method. 
InputMethodSubtype This class is used to specify meta information of a subtype contained in an input method editor (IME). 
InputMethodSubtype.InputMethodSubtypeBuilder InputMethodSubtypeBuilder is a builder class of InputMethodSubtype.