微信小程序中动画多次调用的问题

function hideMsg(that) {
  var animation = wx.createAnimation({
    duration: 1500,
    timingFunction: 'linear',
  })

  that.animation = animation

  animation.opacity(0).step()

  that.setData({
    animationData: animation.export()
  })

  setTimeout(() => {
    animation.opacity(1).step()
    that.setData({
      sendMsg: '',
      animationData: animation.export()
    })
  }, 1200)
}

每次调用结束后，都会将动画重置，这是重复调用的核心！