title: Android two way binding with Integer type causes databinding does not exist
body: <p>I'm having some issue with implementing two way binding with an Integer data type.</p>
  
  <pre><code>public class User {
  
      private String firstName;
      private String lastName;
      private int age;
  
      public User() {}
  
      public void setFirstName(String firstName) {
         this.firstName = firstName;
      }
  
      public String getFirstName() {
         return this.firstName;
      }
  
      public void setLastName(String lastName) {
         this.lastName = lastName;
      }
  
      public String getLastName() {
         return this.lastName;
      }
  
      public void setAge(int age) {
         this.age = age;
      }
  
      public int getAge() {
         return this.age;
      }
  
  }
  </code></pre>
  
  <p><strong>XML:</strong></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;layout xmlns:android="http://schemas.android.com/apk/res/android"&gt;
  
      &lt;data class="UserDataBinding"&gt;
          &lt;variable
              name="user"
              type="com.databinding.model.User" /&gt;
      &lt;/data&gt;
  
      &lt;LinearLayout
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:orientation="vertical"
              android:padding="@dimen/activity_horizontal_margin"&gt;
  
         &lt;EditText android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:text="@={user.firstName}" /&gt;
  
         &lt;EditText android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:text="@={user.lastName}" /&gt;
  
         &lt;EditText android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:text="@={user.age}" /&gt;
  
      &lt;/LinearLayout&gt;
  &lt;/layout&gt;
  </code></pre>
  
  <p>Unfortunately, it gives me the error </p>
  
  <blockquote>
    <p>"Error:(52, 17) Cannot find the getter for attribute 'android:text'
    with value type java.lang.Integer on
    android.support.design.widget.TextInputEditText. "</p>
  </blockquote>
  
  <p>If I change the attribute text to </p>
  
  <pre><code>       &lt;EditText android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:text="@={Integer.toString(user.age)}" /&gt;
  </code></pre>
  
  <p>then I get the error </p>
  
  <blockquote>
    <p>"Error:cannot generate view binders java.lang.NullPointerException"</p>
  </blockquote>
  
  <p>Appreciate any help on this.</p>
  
  <p>UPDATE: It seems there was another error right after the error mentioned above.</p>
  
  <blockquote>
    <p>cannot generate view binders java.lang.NullPointerException</p>
  </blockquote>
  
  <p>Not sure why its giving me NPE even though the app hasn't started yet.</p>