title: java.lang.UnsupportedOperationException: Can't convert to dimension: type=0x12 in android
body: <p>I'm getting the above error with my xml below. What is my issue?</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"&gt;
  
    &lt;TextView
      android:id="@+id/question"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_marginLeft="20dp"
      android:layout_marginTop="20dp"
      android:text="what is your name?"
      android:textColor="@android:color/black" /&gt;
  
    &lt;RadioGroup
      android:id="@+id/answer_group"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_below="@+id/question"
      android:layout_marginLeft="20dp"
      android:layout_marginTop="10dp" &gt;
  
      &lt;RelativeLayout
        android:id="@+id/radio_group_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" &gt;
  
        &lt;RadioButton
          android:id="@+id/option1"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="paru"
          android:textColor="@android:color/black" /&gt;
  
        &lt;RadioButton
          android:id="@+id/option2"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_marginLeft="20dp"
          android:layout_toRightOf="@id/option1"
          android:text="mani"
          android:textColor="@android:color/black" /&gt;
  
        &lt;RadioButton
          android:id="@+id/option3"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_below="@id/option1"
          android:text="sankar"
          android:textColor="@android:color/black" /&gt;
  
        &lt;RadioButton
          android:id="@+id/option4"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_below="@id/option2"
          android:layout_marginLeft="@id/option2"
          android:layout_toRightOf="@id/option3"
          android:text="venkat"
          android:textColor="@android:color/black" /&gt;
  
      &lt;/RelativeLayout&gt;
    &lt;/RadioGroup&gt;
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>and my logcat shows:</p>
  
  <pre><code>java.lang.UnsupportedOperationException: Can't convert to dimension: type=0x12
      at android.content.res.TypedArray.getDimensionPixelSize(TypedArray.java:463)
      at android.view.ViewGroup$MarginLayoutParams.&lt;init&gt;(ViewGroup.java:5768)
  </code></pre>