Please modify this method according to your need. This worked for me!
private boolean validateMobilenumber() {
if (mobilenumber.getText().toString().trim().isEmpty() || mobilenumber.getText().toString().length() < 10) {
input_layout_mobilenumber.setErrorEnabled(true);
input_layout_mobilenumber.setError(getString(R.string.err_msg_mobilenumber));
// requestFocus(mobilenumber);
return false;
} else {
input_layout_mobilenumber.setError(null);
input_layout_mobilenumber.setErrorEnabled(false);
mobilenumber.setBackground(mobilenumber.getBackground().getConstantState().newDrawable());
}