如何在swift上打开和关闭sprite kit动画

Im creating a game and i am trying to implement a run animation on a character. The animation consists of 30 frames being ran at 30fps. the animation works fine however I'm having trouble looping the animation when walking, i have created a button linked with the hero movement however with the current coding when the button is held down the animation only loops the first frame and when the button is release the full animation is played. I have tried to implement a SKwaitForduration action but that did not work either and now I'm pretty stumped. Any help is good help lol I'm very new to animation Im creating a game and i am trying to implement