wx.createAnimation 编译时没有动画效果，直接进入最后一帧，请问如何解决？
var animationData = wx.createAnimation({
delay:100,
duration: 800,
timingFunction: 'ease'
})
this.animationData = animationData
this.animationData.opacity(1).step()
this.setData({
animate: this.animationData.export()
})
