Rename sample adapter: AnimalsAdapter and fix it's getItemId()

Fixes timehop#80

Author: webmaster128

sample/src/main/java/com/timehop/stickyheadersrecyclerview/sample/RecyclerArrayAdapter.java renamed to sample/src/main/java/com/timehop/stickyheadersrecyclerview/sample/AnimalsAdapter.java

@@ -7,32 +7,35 @@
 import java.util.Collection;
 
 
-public abstract class RecyclerArrayAdapter<M, VH extends RecyclerView.ViewHolder>
+/**
+ * Adapter holding a list of animal names of type String. Note that each item must be unique.
+ */
+public abstract class AnimalsAdapter<VH extends RecyclerView.ViewHolder>
     extends RecyclerView.Adapter<VH> {
-  private ArrayList<M> items = new ArrayList<M>();
+  private ArrayList<String> items = new ArrayList<String>();
 
-  public RecyclerArrayAdapter() {
+  public AnimalsAdapter() {
     setHasStableIds(true);
   }
 
-  public void add(M object) {
+  public void add(String object) {
     items.add(object);
     notifyDataSetChanged();
   }
 
-  public void add(int index, M object) {
+  public void add(int index, String object) {
     items.add(index, object);
     notifyDataSetChanged();
   }
 
-  public void addAll(Collection<? extends M> collection) {
+  public void addAll(Collection<? extends String> collection) {
     if (collection != null) {
       items.addAll(collection);
       notifyDataSetChanged();
     }
   }
 
-  public void addAll(M... items) {
+  public void addAll(String... items) {
     addAll(Arrays.asList(items));
   }
 
@@ -41,18 +44,18 @@ public void clear() {
     notifyDataSetChanged();
   }
 
-  public void remove(M object) {
+  public void remove(String object) {
     items.remove(object);
     notifyDataSetChanged();
   }
 
-  public M getItem(int position) {
+  public String getItem(int position) {
     return items.get(position);
   }
 
   @Override
   public long getItemId(int position) {
-    return position;
+    return getItem(position).hashCode();
   }
 
   @Override

sample/src/main/java/com/timehop/stickyheadersrecyclerview/sample/MainActivity.java

@@ -8,7 +8,6 @@
 import android.os.Looper;
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
-import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -35,22 +34,22 @@ protected void onCreate(Bundle savedInstanceState) {
     final ToggleButton isReverseButton = (ToggleButton) findViewById(R.id.button_is_reverse);
 
     // Set adapter populated with example dummy data
-    final SampleArrayHeadersAdapter mAdapter = new SampleArrayHeadersAdapter();
-    mAdapter.add("Animals below!");
-    mAdapter.addAll(getDummyDataSet());
-    recyclerView.setAdapter(mAdapter);
+    final AnimalsHeadersAdapter adapter = new AnimalsHeadersAdapter();
+    adapter.add("Animals below!");
+    adapter.addAll(getDummyDataSet());
+    recyclerView.setAdapter(adapter);
 
     // Set button to update all views one after another (Test for the "Dance")
     button.setOnClickListener(new View.OnClickListener() {
       @Override
       public void onClick(View v) {
         Handler handler = new Handler(Looper.getMainLooper());
-        for (int i = 0; i < mAdapter.getItemCount(); i++) {
+        for (int i = 0; i < adapter.getItemCount(); i++) {
           final int index = i;
           handler.postDelayed(new Runnable() {
             @Override
             public void run() {
-              mAdapter.notifyItemChanged(index);
+              adapter.notifyItemChanged(index);
             }
           }, 50);
         }
@@ -63,7 +62,7 @@ public void run() {
     recyclerView.setLayoutManager(layoutManager);
 
     // Add the sticky headers decoration
-    final StickyRecyclerHeadersDecoration headersDecor = new StickyRecyclerHeadersDecoration(mAdapter);
+    final StickyRecyclerHeadersDecoration headersDecor = new StickyRecyclerHeadersDecoration(adapter);
     recyclerView.addItemDecoration(headersDecor);
 
     // Add decoration for dividers between list items
@@ -84,10 +83,10 @@ public void onHeaderClick(View header, int position, long headerId) {
     recyclerView.addOnItemTouchListener(new RecyclerItemClickListener(this, new RecyclerItemClickListener.OnItemClickListener() {
       @Override
       public void onItemClick(View view, int position) {
-        mAdapter.remove(mAdapter.getItem(position));
+        adapter.remove(adapter.getItem(position));
       }
     }));
-    mAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
+    adapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
       @Override
       public void onChanged() {
         headersDecor.invalidateHeaders();
@@ -100,7 +99,7 @@ public void onClick(View v) {
         boolean isChecked = isReverseButton.isChecked();
         isReverseButton.setChecked(isChecked);
         layoutManager.setReverseLayout(isChecked);
-        mAdapter.notifyDataSetChanged();
+        adapter.notifyDataSetChanged();
       }
     });
   }
@@ -117,7 +116,7 @@ private int getLayoutManagerOrientation(int activityOrientation) {
     }
   }
 
-  private class SampleArrayHeadersAdapter extends RecyclerArrayAdapter<String, RecyclerView.ViewHolder>
+  private class AnimalsHeadersAdapter extends AnimalsAdapter<RecyclerView.ViewHolder>
       implements StickyRecyclerHeadersAdapter<RecyclerView.ViewHolder> {
     @Override
     public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {