TextWatcher | API reference | Android Developers

public interface TextWatcher
implements NoCopySpan

When an object of this type is attached to an Editable, its methods will be called when the text is changed.

Summary

Public methods
`abstract void`	`afterTextChanged(Editable s)` This method is called to notify you that, somewhere within `s`, the text has been changed.
`abstract void`	`beforeTextChanged(CharSequence s, int start, int count, int after)` This method is called to notify you that, within `s`, the `count` characters beginning at `start` are about to be replaced by new text with length `after`.
`abstract void`	`onTextChanged(CharSequence s, int start, int before, int count)` This method is called to notify you that, within `s`, the `count` characters beginning at `start` have just replaced old text that had length `before`.

Public methods

afterTextChanged

public abstract void afterTextChanged (Editable s)

This method is called to notify you that, somewhere within s, the text has been changed. It is legitimate to make further changes to s from this callback, but be careful not to get yourself into an infinite loop, because any changes you make will cause this method to be called again recursively. (You are not told where the change took place because other afterTextChanged() methods may already have made other changes and invalidated the offsets. But if you need to know here, you can use Spannable.setSpan in onTextChanged(CharSequence, int, int, int) to mark your place and then look up from here where the span ended up.

Parameters
`s`	`Editable`

beforeTextChanged

public abstract void beforeTextChanged (CharSequence s, 
                int start, 
                int count, 
                int after)

This method is called to notify you that, within s, the count characters beginning at start are about to be replaced by new text with length after. It is an error to attempt to make changes to s from this callback.

Parameters
`s`	`CharSequence`
`start`	`int`
`count`	`int`
`after`	`int`

onTextChanged

public abstract void onTextChanged (CharSequence s, 
                int start, 
                int before, 
                int count)

This method is called to notify you that, within s, the count characters beginning at start have just replaced old text that had length before. It is an error to attempt to make changes to s from this callback.

Parameters
`s`	`CharSequence`
`start`	`int`
`before`	`int`
`count`	`int`

Content and code samples on this page are subject to the licenses described in the Content License. Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.