It worked for me this way, it's the best I've found. It is for a max length of 200 characters
editObservations.addTextChangedListener(new TextWatcher() {
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
if (editObservations.getText().length() >= 201){
String str = editObservations.getText().toString().substring(0, 200);
editObservations.setText(str);
editObservations.setSelection(str.length());
}
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
}
@Override
public void afterTextChanged(Editable s) {
}
});