The Android framework provides the EditText interface element to allow the entry and editing of text. There are some use cases where one might need to detect text changes as they are typed in the EditText and react accordingly. One use case could be showing auto suggest values. The TextWatcher interface can be used for listening in for changes in text in an EditText. This interface has three abstract methods - afterTextChanged(Editable s) beforeTextChanged(CharSequence s, int start, int count, int after) onTextChanged(CharSequence s, int start, int before, int count) Wiring the TextWatcher to the EditText If you take a look at EditText’s documentation, you won’t see any obvious way to wire the TextWatcher to it.