Fix issue #287 - crash with deleting / redrafting a reply

app/src/main/java/app/fedilab/android/activities/ComposeActivity.java

@@ -386,9 +386,11 @@ public class ComposeActivity extends BaseActivity implements ComposeAdapter.Mana
             });
 
         } else {
+            if (composeAdapter != null) {
                 composeAdapter.addSharing(null, null, sharedDescription, null, sharedContent, null);
             }
         }
+    }
 
     @Override
     protected void onDestroy() {