fixed fab not hiding when going back from settings to create frag

app/src/main/java/net/headlezz/notificationlogger/MainActivity.java

@@ -45,6 +45,13 @@ public class MainActivity extends AppCompatActivity {
         }
     }
 
+    @Override
+    protected void onResume() {
+        super.onResume();
+        if(getSupportFragmentManager().getBackStackEntryCount() > 0)
+            mFAB.setVisibility(View.GONE);
+    }
+
     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         getMenuInflater().inflate(R.menu.main_activity, menu);