title: XML tools context error
body: <p>I am currently learning android development for a university module so I am sorry if this is a very basic error. I am currently just following <a href="http://www.androidhive.info/2012/01/android-login-and-registration-with-php-mysql-and-sqlite/" rel="nofollow">this tutorial</a>, understanding how android java differs to normal java and so on. </p>
  
  <p>On the <strong>XML file activity_main</strong> I am getting the following error:</p>
  
  <blockquote>
    <p>Cannot resolve symbol ${relativePackage}.${activityClass}
    Validates resource references inside Android XML Files</p>
  </blockquote>
  
  <p>I have used Google and StackOverflow search to look at possible solutions, I found some articles stating it can be due to bad XML formatting which is where I believe the error is. I have also tried to run the project and it cant find the class file R. I have cleaned and rebuilt the project but the error continues to happen.</p>
  
  <p><a href="https://drive.google.com/file/d/0B4vL9wnJulKoR1ByZEY3Z05yZGM/view?usp=sharing" rel="nofollow">Here is my code if you would like to take a look</a>. Although at the moment it is very similar to the tutorial website.</p>
  
  <p>My xml:</p>
  
  <pre><code>&lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     tools:context="${relativePackage}.${activityClass}" &gt;
  
      &lt;LinearLayout
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:layout_centerInParent="true"
         android:layout_marginLeft="20dp"
         android:layout_marginRight="20dp"
         android:gravity="center"
         android:orientation="vertical" &gt;
  
          &lt;TextView
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:text="@string/welcome"
             android:textSize="20dp" /&gt;
  
          &lt;TextView
             android:id="@+id/name"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:padding="10dp"
             android:textColor="@color/lbl_name"
             android:textSize="24dp" /&gt;
  
          &lt;TextView
             android:id="@+id/email"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:textSize="13dp" /&gt;
  
          &lt;Button
             android:id="@+id/btnLogout"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:layout_marginTop="40dip"
             android:background="@color/btn_logut_bg"
             android:text="@string/btn_logout"
             android:textAllCaps="false"
             android:textColor="@color/white"
             android:textSize="15dp" /&gt;
      &lt;/LinearLayout&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>Any help is much appreicated, thank you</p>
  
  <p><em>P.S I am using Android Studio</em></p>