void OnGUI() { if (GUI.Button(new Rect(0, 0, 100, 50), onRunning?"Stop":"Start")) { if (onRunning) { onRunning = false; action.Stop(); } else { onRunning = true; action.Continue(); } } if (GUI.Button(new Rect(0, 50, 100, 50), "Restart")) { onRunning = true; action.Restart(); } }