code: public void setLoop(boolean doLoop, GVRContext gvrContext) {
          if (this.loop != doLoop ) {
              // a change in the loop
              for (GVRNodeAnimation gvrKeyFrameAnimation : gvrKeyFrameAnimations) {
                  if (doLoop) gvrKeyFrameAnimation.setRepeatMode(GVRRepeatMode.REPEATED);
                  else gvrKeyFrameAnimation.setRepeatMode(GVRRepeatMode.ONCE);
              }
              // be sure to start the animations if loop is true
              if ( doLoop ) {
                  for (GVRNodeAnimation gvrKeyFrameAnimation : gvrKeyFrameAnimations) {
                      gvrKeyFrameAnimation.start(gvrContext.getAnimationEngine() );
                  }
              }
              this.loop = doLoop;
          }
      }
docs: SetLoop will either set the GVRNodeAnimation's Repeat Mode to REPEATED if loop is true.
  or it will set the GVRNodeAnimation's Repeat Mode to ONCE if loop is false
  if loop is set to TRUE, when it was previously FALSE, then start the Animation.
  @param doLoop
  @param gvrContext