IshankGulati · December 2, 2020 07:54 · Oct 19, 2016 · Oct 17, 2016
diff --git a/RecyclerViewBaseViewHolder.java b/RecyclerViewBaseViewHolder.java
@@ -57,9 +57,4 @@ public final boolean onLongClick(View view) {
     public final void update(RecyclerViewItemClickListener listener){
         this.listener = listener;
     }
-
-    /**
-     * Method is used to set onClickListeners on required views.
-     */
-    public abstract void bindListeners();
 }
diff --git a/RVObserver.java b/RVObserver.java
@@ -0,0 +1,8 @@
+/**
+ * Created by Ishank Gulati on 14/10/16.
+ * Observer as per Observer design pattern.
+ */
+
+public interface RVObserver {
+    void update(RecyclerViewItemClickListener listener);
+}
diff --git a/RVobservable.java b/RVobservable.java
@@ -0,0 +1,10 @@
+/**
+ * Created by Ishank Gulati on 14/10/16.
+ * Subject as per Observer design pattern.
+ */
+
+public interface RVObservable {
+    void registerObserver(RVObserver o);
+    void notifyListenerAttached();
+    void removeObserver();
+}
diff --git a/RecyclerViewBaseAdapter.java b/RecyclerViewBaseAdapter.java
@@ -0,0 +1,98 @@
+import android.support.v7.widget.RecyclerView;
+import android.view.ViewGroup;
+
+
+import java.util.List;
+
+
+/**
+ * Created by Ishank Gulati on 14/10/16.
+ * Base adapter to be extended by all the recycler view adapters.
+ */
+
+public abstract class RecyclerViewBaseAdapter<T, VH extends RecyclerViewBaseViewHolder> extends
+        RecyclerView.Adapter<VH> implements RVObservable{
+
+    protected List<T> items;
+    private RecyclerViewItemClickListener listener;
+    private RVObserver observer;
+
+    @Override
+    public final VH onCreateViewHolder(ViewGroup parent, int viewType) {
+        VH vh = onCreateRecyclerViewHolder(parent, viewType);
+        notifyListenerAttached();
+        return vh;
+    }
+
+    @Override
+    public final void onBindViewHolder(VH holder, int position) {
+        if (items != null) {
+            holder.performBind(items.get(position), position);
+        }
+        onBindRecyclerViewHolder(holder, position);
+    }
+
+    /**
+     * Functionality of onCreateViewHolder has been moved here. User should override this when using
+     * this class
+     * @param parent The ViewGroup into which the new View will be added after it is bound to
+     *               an adapter position.
+     * @param viewType The view type of the new View.
+     * @return A new ViewHolder that holds a View of the given view type.
+     */
+    public abstract VH onCreateRecyclerViewHolder(ViewGroup parent, int viewType);
+
+    /**
+     * Functionality of onBindViewHolder has been moved here. User should override this when using
+     * this class
+     * @param holder The ViewHolder which should be updated to represent the contents of the
+     *               item at the given position in the data set.
+     * @param position The position of the item within the adapter's data set.
+     */
+    public abstract void onBindRecyclerViewHolder(VH holder, int position);
+
+    /**
+     * Method used to set on item click listener of Recycler view.
+     * @param listener An implementation of RecyclerViewItemClickListener
+     */
+    public void setOnItemClickListener(RecyclerViewItemClickListener listener){
+        this.listener = listener;
+        notifyListenerAttached();
+    }
+
+    /**
+     * Used to update adapter's data
+     * @param items adapter's data
+     */
+    public void setDataset(List<T> items) {
+        this.items = items;
+        notifyDataSetChanged();
+    }
+
+    /**
+     * Used to register view holder in adapter.
+     * @param o view holder implementing observer interface.
+     */
+    @Override
+    public final void registerObserver(RVObserver o) {
+        this.observer = o;
+    }
+
+    /**
+     * Used to remove registered view holder in adapter.
+     */
+    @Override
+    public final void removeObserver() {
+        this.observer = null;
+    }
+
+    /**
+     * Used to notify view holder that on click listener of recycler view has been updated.
+     */
+    @Override
+    public final void notifyListenerAttached(){
+        if (observer != null && listener != null) {
+            observer.update(listener);
+        }
+    }
+}
diff --git a/RecyclerViewBaseViewHolder.java b/RecyclerViewBaseViewHolder.java
@@ -0,0 +1,65 @@
+import android.support.v7.widget.RecyclerView;
+import android.view.View;
+
+/**
+ * Created by Ishank Gulati on 14/10/16.
+ *  Base view holder to be extended by all the recycler view view holders.
+ */
+
+public abstract class RecyclerViewBaseViewHolder<T> extends RecyclerView.ViewHolder implements View.OnClickListener,
+        View.OnLongClickListener, RVObserver{
+    protected T item;
+    protected int position;
+    private RecyclerViewItemClickListener listener;
+    private RVObservable observable;
+
+    protected RecyclerViewBaseViewHolder(View itemView, RVObservable observable) {
+        super(itemView);
+        this.observable = observable;
+        observable.registerObserver(this);
+    }
+
+    /**
+     * Used to bind items to view holder.
+     * @param item item within the adapter's data set
+     * @param position The position of the item within the adapter's data set
+     */
+    protected final void performBind(T item, int position) {
+        this.item = item;
+        this.position = position;
+    }
+
+    /**
+     * onClick has been delegated to fragment having recycler view.
+     * @param view view which is clicked
+     */
+    @Override
+    public final void onClick(View view) {
+        if(listener != null) {
+            listener.onClick(view, item);
+        }
+    }
+
+    /**
+     * onLongClick has been delegated to fragment having recycler view.
+     * @param view view which is clicked
+     */
+    @Override
+    public final boolean onLongClick(View view) {
+        return listener != null && listener.onLongClick(view, item);
+    }
+
+    /**
+     * Used to update view holder with a listener listening to all the clicks on recycler view.
+     * @param listener An implementation of RecyclerViewItemClickListener
+     */
+    @Override
+    public final void update(RecyclerViewItemClickListener listener){
+        this.listener = listener;
+    }
+
+    /**
+     * Method is used to set onClickListeners on required views.
+     */
+    public abstract void bindListeners();
+}
diff --git a/RecyclerViewItemClickListener.java b/RecyclerViewItemClickListener.java
@@ -0,0 +1,10 @@
+import android.view.View;
+
+/**
+ * Created by Ishank Gulati on 14/10/16.
+ */
+
+public interface RecyclerViewItemClickListener<T> {
+    void onClick(View view, T item);
+    boolean onLongClick(View view, T item);
+}