参数 描述 track The animation track to set the frame of. index The new index for the animation frame.
This function will set the animation assigned to the given track to the frame you supply. The frame index should be an real value between 0 and the number of frames for the animation (which you can get using the function skeleton_animation_get_frames). If you supply a value outside of this range, the animation will be looped to make up the difference, for example if the animation has 5 frames and you set the frame to 8, the actual frame shown will be 3.重要！该函数在试用版（Trial License）产品中不可用。
The above code will set the frame index for the animation in track 0 to the negative image speed when the global "pause" variable is true (essentially pausing the animation).