Support FastScroller

Make AdapterWrapper extend BaseAdapter because that is what
FastScroller wants.

CHANGELOG.md

@@ -6,6 +6,7 @@ Changelog
 
 * Fix #77: OnClickListener in list item crashes
 DragSortController.
+* Fix #81: Enabling FastScroller causes crash.
 
 0.6.0
 -----

demo/res/layout/warp_main.xml

@@ -1,4 +1,26 @@
 <?xml version="1.0" encoding="utf-8"?>
-<merge>
-    <include layout="@layout/hetero_main"/>
-</merge>
+<com.mobeta.android.dslv.DragSortListView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:dslv="http://schemas.android.com/apk/res/com.mobeta.android.demodslv"
+    android:id="@android:id/list"
+    android:layout_width="fill_parent"
+    android:layout_height="fill_parent"
+    android:paddingTop="0dp"
+    android:paddingBottom="0dp"
+    android:paddingLeft="10dp"
+    android:layout_margin="10dp"
+    android:dividerHeight="5dp"
+    android:fastScrollEnabled="true"
+    dslv:drag_enabled="true"
+    dslv:collapsed_height="2dp"
+    dslv:drag_scroll_start="0.33"
+    dslv:max_drag_scroll_speed="0.5"
+    dslv:float_alpha="0.6"
+    dslv:slide_shuffle_speed="0.3"
+    dslv:track_drag_sort="false"
+    dslv:use_default_controller="true"
+    dslv:drag_handle_id="@id/drag_handle"
+    dslv:sort_enabled="true"
+    dslv:remove_enabled="true"
+    dslv:drag_start_mode="onDown"
+    dslv:remove_mode="flingRemove" />

library/src/com/mobeta/android/dslv/DragSortListView.java

@@ -602,9 +602,8 @@ public void setMaxScrollSpeed(float max) {
      */
     @Override
     public void setAdapter(ListAdapter adapter) {
-        mAdapterWrapper = new AdapterWrapper(adapter);
-
         if (adapter != null) {
+            mAdapterWrapper = new AdapterWrapper(adapter);
             adapter.registerDataSetObserver(mObserver);
 
             if (adapter instanceof DropListener) {
@@ -616,6 +615,8 @@ public void setAdapter(ListAdapter adapter) {
             if (adapter instanceof RemoveListener) {
                 setRemoveListener((RemoveListener) adapter);
             }
+        } else {
+            mAdapterWrapper = null;
         }
 
         super.setAdapter(mAdapterWrapper);
@@ -719,7 +720,7 @@ public View getView(int position, View convertView, ViewGroup parent) {
                 if (child != oldChild) {
                     // shouldn't get here if user is reusing convertViews
                     // properly
-                        v.removeViewAt(0);
+                    v.removeViewAt(0);
                     v.addView(child);
                 }
             } else {