Android APIs
Added in API level 1
package

android.text.method

Provides classes that monitor or modify keypad input.

You can use these classes to modify the type of keypad entry for your application, or decipher the keypresses entered for your specific entry method. For example:

// Set the text to password display style:
EditText txtView = (EditText)findViewById(R.id.text);
txtView.setTransformationMethod(PasswordTransformationMethod.getInstance());

//Set the input style to numbers, rather than qwerty keyboard style.
txtView.setInputMethod(DigitsInputMethod.getInstance());

// Find out whether the caps lock is on.
// 0 is no, 1 is yes, 2 is caps lock on.
int active = MultiTapInputMethod.getCapsActive(txtView.getText());

Interfaces

KeyListener Interface for converting text key events into edit operations on an Editable class. 
MovementMethod Provides cursor positioning, scrolling and text selection functionality in a TextView
TransformationMethod TextView uses TransformationMethods to do things like replacing the characters of passwords with dots, or keeping the newline characters from causing line breaks in single-line text fields. 

Classes

ArrowKeyMovementMethod A movement method that provides cursor movement and selection. 
BaseKeyListener Abstract base class for key listeners. 
BaseMovementMethod Base classes for movement methods. 
CharacterPickerDialog Dialog for choosing accented characters related to a base character. 
DateKeyListener For entering dates in a text field. 
DateTimeKeyListener For entering dates and times in the same text field. 
DialerKeyListener For dialing-only text entry

As for all implementations of KeyListener, this class is only concerned with hardware keyboards. 
DigitsKeyListener For digits-only text entry

As for all implementations of KeyListener, this class is only concerned with hardware keyboards. 
HideReturnsTransformationMethod This transformation method causes any carriage return characters (\r) to be hidden by displaying them as zero-width non-breaking space characters (). 
LinkMovementMethod A movement method that traverses links in the text buffer and scrolls if necessary. 
MetaKeyKeyListener This base class encapsulates the behavior for tracking the state of meta keys such as SHIFT, ALT and SYM as well as the pseudo-meta state of selecting text. 
MultiTapKeyListener This is the standard key listener for alphabetic input on 12-key keyboards. 
NumberKeyListener For numeric text entry

As for all implementations of KeyListener, this class is only concerned with hardware keyboards. 
PasswordTransformationMethod  
QwertyKeyListener This is the standard key listener for alphabetic input on qwerty keyboards. 
ReplacementTransformationMethod This transformation method causes the characters in the getOriginal() array to be replaced by the corresponding characters in the getReplacement() array. 
ScrollingMovementMethod A movement method that interprets movement keys by scrolling the text buffer. 
SingleLineTransformationMethod This transformation method causes any newline characters (\n) to be displayed as spaces instead of causing line breaks, and causes carriage return characters (\r) to have no appearance. 
TextKeyListener This is the key listener for typing normal text. 
TimeKeyListener For entering times in a text field. 
Touch  

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