addTextChangedListener.java

textView.addTextChangedListener(new TextWatcher() {

    public void afterTextChanged(Editable s) {
        //do something
    }

    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        //do something
    }

    public void onTextChanged(CharSequence s, int start, int before, int count) {
        //do something
    }
});