FirstName field Validations in Android Studio
<p><a href="http://i.stack.imgur.com/snEfB.png" rel="nofollow">Sample code format</a></p>

<p>Hello everyone, I have added this line of code for validation to check whether the first name field contains numbers or special characters however, upon testing it it seems the firstname always shows error 
can anyone pls help. big thanks!</p>

<pre><code>    (!isNetworkAvailable()) {
        showSweetDialog(AppConstants.ERR_CONNECTION, "error", false, null, null);
    }   else if (firstName.isEmpty()) {
        setError(etFirstName, AppConstants.WARN_FIELD_REQUIRED);
    } 

   else if(!firstName.matches("[a-zA-Z]")){
        setError(etFirstName, AppConstants.WARN_FIELD_REQUIRED);
    } 


else if (lastName.isEmpty()) {
        setError(etLastName, AppConstants.WARN_FIELD_REQUIRED);
    }  else if (mobile.isEmpty()) {
        setError(etMobile, AppConstants.WARN_FIELD_REQUIRED);
    } else if (email.isEmpty()) {
        setError(etEmail, AppConstants.WARN_FIELD_REQUIRED);
    } else if (password.isEmpty()) {
        setError(etPassword, AppConstants.WARN_FIELD_REQUIRED);
    }  else if (!Patterns.EMAIL_ADDRESS.matcher(email).matches()) {
        setError(etEmail, AppConstants.WARN_INVALID_EMAIL_FORMAT);
    } else if (address.isEmpty()) {
        setError(etAddress, AppConstants.WARN_FIELD_REQUIRED);
    } else {
</code></pre>