Angular form Validation messages not appearing - angularjs

Question

I'm missing something simple I am sure of it, but my form validation messages never appear in the following code.
<form name="loginform" ng-controller="controllers.LoginController" ng-submit="loginUser(loginform.$valid)" novalidate>
<fieldset>
<br/>
<legend><h3>Account Login</h3></legend>
<div class="{ 'has-error' : loginform.username.$invalid && !loginform.username.$pristine }">
<label>Username:</label>
<input type="text" ng-model="username" name="username" placeholder="username" class="form-control" required><span ng-show="loginform.username.$invalid && !loginform.username.$pristine" class="help-block">Required!</span>
</div>
<br/>
<div class="{ 'has-error' : loginform.password.$invalid && !loginform.password.$pristine }">
<label>Password:</label>
<input type="password" name="password" ng-model="password" placeholder="password" class="form-control" required><span ng-show="loginform.password.$invalid && !loginform.password.$pristine" class="help-block">Required!</span>
</div>
<div class="form-group">
<button type="submit" class="btn btn-primary" >Submit</button>
Login
</div>
</fieldset>
</form>
controllers.LoginController = function ($scope, $location, AuthFactory, Page) {
'use strict';
$scope.username = null;
$scope.password = null;
$scope.loginUser = function (isValid) {

Answer 1

The $pristine check was the problem... Here are the corrections...
<form name="loginform" ng-submit="loginUser(loginform.$valid)" novalidate>
<fieldset>
<br/>
<legend><h3>Account Login</h3></legend>
<div class="form-group" ng-class="{ 'has-error' : loginform.password.$invalid && submitted }">
<label>Username:</label>
<input type="text" ng-model="username" name="username" placeholder="username" class="form-control" ng-required="true" required><span ng-show="loginform.username.$invalid && submitted" class="help-block">Required!</span>
</div>
<br/>
<div class="form-group" ng-class="{ 'has-error' : loginform.password.$invalid && submitted }">
<label>Password:</label>
<input type="password" name="password" ng-model="password" placeholder="password" class="form-control" required><span ng-show="loginform.password.$invalid && submitted" class="help-block">Required!</span>
</div>
<div class="form-group">
<button type="submit" class="btn btn-primary" >Submit</button>
Login
</div>
</fieldset>
</form>

Answer 2

If your application is form heavy, consider using this thirdparty ngValidate module.
<input name="demo-field-1" ng-model="user.name" ng-validate="custom-strategy">
The directive will add a span to hold your error messages. You can define custom validation strategies and individual error messages.
demo plnkr