如何在角度js中提交表单时显示验证消息

I have form in which there are couple of text fields and an email field. I want to validate all fields for required / mandatory validation. I want to validate email field for email format validation. I want to carry out validation only when I click on two buttons and show the validation messages at top of the page. I know that I can check for email and required validations on field and using ng-show and a flag I can show messages. However I want to check each field's value in a directive and then set the flag to true which will make the message appear.I have form in which there are couple of text f