Don't exit on back pressed if a trace is activated.

app/src/main/java/fr/chteufleur/mytrackingdog/MainActivity.java

@@ -281,6 +281,11 @@ public class MainActivity extends AppCompatActivity implements IOrientationConsu
 
     @Override
     public void onBackPressed() {
+        if (serviceGps.isDogActivated() || serviceGps.isTraceurActivated()) {
+            Toast.makeText(ctx, "Une trace est en cours d'enregistrement.", Toast.LENGTH_LONG).show();
+            return ;
+        }
+
         super.onBackPressed();
         pause();
         if (serviceGps != null) {