diff --git a/clients/Android/app/src/main/java/org/mtuosc/techchat/activity/PostActivity.java b/clients/Android/app/src/main/java/org/mtuosc/techchat/activity/PostActivity.java
index 6c1ac91..a69a873 100644
--- a/clients/Android/app/src/main/java/org/mtuosc/techchat/activity/PostActivity.java
+++ b/clients/Android/app/src/main/java/org/mtuosc/techchat/activity/PostActivity.java
@@ -94,12 +94,14 @@ public boolean onOptionsItemSelected(MenuItem item) {
                 if (! item.isChecked()) {
                     // call the sort function
                     item.setChecked(true);
+                    adapter.sortPosts(PostAdapter.NEWEST);
                 }
                 break;
             case R.id.menu_sort_oldest:
                 if (! item.isChecked()) {
-                    // call the sort function
+
                     item.setChecked(true);
+                    adapter.sortPosts(PostAdapter.OLDEST);
                 }
                 break;
             case R.id.menu_sort_trending:
diff --git a/clients/Android/app/src/main/java/org/mtuosc/techchat/models/PostAdapter.java b/clients/Android/app/src/main/java/org/mtuosc/techchat/models/PostAdapter.java
index d3f9391..0eeddf4 100644
--- a/clients/Android/app/src/main/java/org/mtuosc/techchat/models/PostAdapter.java
+++ b/clients/Android/app/src/main/java/org/mtuosc/techchat/models/PostAdapter.java
@@ -11,10 +11,17 @@
 import org.mtuosc.techchat.R;
 
 import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
 
 public class PostAdapter extends RecyclerView.Adapter<PostAdapter.PostViewHolder> {
     private ArrayList<Post> posts = new ArrayList<>();
 
+    public static final int NEWEST = 0;
+    public static final int OLDEST = 1;
+    public static final int TRENDING = 2;
+
+
     @NonNull
     @Override
     public PostViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
@@ -53,4 +60,29 @@ public void addPost(Post post) {
     }
 
     public void flushPosts() {posts = new ArrayList<Post>();}
+
+    public void sortPosts(int sortBy) {
+        switch (sortBy) {
+            case NEWEST: {
+                Collections.sort(posts, new Comparator<Post>() {
+                    @Override
+                    public int compare(Post post, Post t1) {
+                        return post.getTimestamp().compareTo(t1.getTimestamp());
+                    }
+                });
+                this.notifyDataSetChanged();
+                break;
+            }
+            case OLDEST: {
+                Collections.sort(posts, new Comparator<Post>() {
+                    @Override
+                    public int compare(Post post, Post t1) {
+                        return post.getTimestamp().compareTo(t1.getTimestamp()) * -1;
+                    }
+                });
+                this.notifyDataSetChanged();
+                break;
+            }
+        }
+    }
 }