微信小程序自定义底部弹出框

<view class="commodity_screen" bindtap="hidemodal" wx:if="{{showmodalstatus}}"></view>
<view animation="{{animationdata}}" class="commodity_attr_box" wx:if="{{showmodalstatus}}"></view>

.commodity_screen {
 width: 100%;
 height: 100%;
 position: fixed;
 top: 0;
 left: 0;
 background: #000;
 opacity: 0.2;
 overflow: hidden;
 z-index: 1000;
 color: #fff;
}

.commodity_attr_box {
 width: 100%;
 overflow: hidden;
 position: fixed;
 bottom: 0;
 left: 0;
 z-index: 2000;
 background: #fff;
 padding-top: 20rpx;
}

 showmodal: function () {
  // 显示遮罩层
  var animation = wx.createanimation({
   duration: 200,
   timingfunction: "linear",
   delay: 0
  })
  this.animation = animation
  animation.translatey(300).step()
  this.setdata({
   animationdata: animation.export(),
   showmodalstatus: true
  })
  settimeout(function () {
   animation.translatey(0).step()
   this.setdata({
    animationdata: animation.export()
   })
  }.bind(this), 200)
 },
 hidemodal: function () {
  // 隐藏遮罩层
  var animation = wx.createanimation({
   duration: 200,
   timingfunction: "linear",
   delay: 0
  })
  this.animation = animation
  animation.translatey(300).step()
  this.setdata({
   animationdata: animation.export(),
  })
  settimeout(function () {
   animation.translatey(0).step()
   this.setdata({
    animationdata: animation.export(),
    showmodalstatus: false
   })
  }.bind(this), 200)
 }