Android - "The following classes could not be found: - (Change to com.example.random.ScrollViewExt, Fix Build Path, Edit XML, Create Class)"

I have extended the ScrollView class to create a class so that can listen for the onScroll event. But it says that the class which i have extended cannot be found. I have tried the options given and none of them seem to work. Here is the code for the XML

   <com.example.random.ScrollViewExt
   android:id="@+id/scrollview1"
   xmlns:android="http://ift.tt/nIICcg"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent">

   <LinearLayout android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:orientation="vertical"
   android:paddingBottom="@dimen/activity_vertical_margin"
   android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin" >

   <TextView
    android:id="@+id/text1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world" />

    </LinearLayout>
    </com.example.random.ScrollViewExt>

And here is the code for the custom class.

    package com.example.random;

    import android.widget.ScrollView;
    import android.content.Context;
     import android.util.AttributeSet;


    public class ScrollViewExt extends ScrollView {
        private ScrollViewListener scrollViewListener = null;
        public ScrollViewExt(Context context) {
              super(context);
         }

         public ScrollViewExt(Context context, AttributeSet attrs, int defStyle) {
              super(context, attrs, defStyle);
        }

        public ScrollViewExt(Context context, AttributeSet attrs) {
            super(context, attrs);
        } 

         public void setScrollViewListener(ScrollViewListener scrollViewListener) {
             this.scrollViewListener = scrollViewListener;
        } 

        @Override
         protected void onScrollChanged(int l, int t, int oldl, int oldt) {
            super.onScrollChanged(l, t, oldl, oldt);
             if (scrollViewListener != null) {
                 scrollViewListener.onScrollChanged(this, l, t, oldl, oldt);
              }
          }
     }

Any idea on what I could do?