Explication détaillée des exemples de menus à tiroirs pour le développement d'applets WeChat

<view id=&#39;id-main-page&#39; class=&#39;main-page&#39; animation=&#39;{{animationData}}&#39; style=&#39;left:{{mainPageLeft}}rpx;&#39;
 bindtouchstart=&#39;onMainPageTouchstart&#39; catchtouchmove=&#39;onMainPageTouchmove&#39; bindtouchend=&#39;onMainPageTouchend&#39; bindtap=&#39;onMainPageTap&#39;>
  <view class="userinfo">
    <image class="userinfo-avatar" src="{{userInfo.avatarUrl}}" background-size="cover"></image>
    <text class="userinfo-nickname">{{userInfo.nickName}}</text>
  </view>
</view>
<view class=&#39;drawer-menu&#39; animation=&#39;{{animationData}}&#39; style=&#39;left:{{drawerMenuLeft}}rpx;&#39;>
  <view class="userinfo">
    <image class="userinfo-avatar" src="{{userInfo.avatarUrl}}" background-size="cover"></image>
    <text class="userinfo-nickname">{{userInfo.nickName2}}</text>
  </view>
</view>

.main-page {
  width:100%;
  height:2000rpx;
  position: absolute;
  top: 0;
  left: 0;
  padding: 200rpx 0;
}

.drawer-menu {
  width: 800rpx;
  height:2000rpx;
  position: absolute;
  top: 0;
  left: -800rpx;
  padding: 200rpx 0;
  background: rgba(22, 22, 22, 1);
  z-index: 800;
}

  drawerMenuMoveData: {
    check: false,   //是否触发滑动操作
    state:0,    //0:初始状态 1:菜单弹出中状态 2:菜单弹入状态中 3:菜单弹出状态
    firstTouchX:0,  //首次触摸X坐标值
    touchCheckX:60,  //触发滑动的触摸X
    moveX:0,   // 滑动操作横向的移动距离
    maxMoveX: (app.globalData.deviceInfo.windowWidth - 60), //抽屉菜单最大移动距离
    lastTranlateX: 0  //上次动画效果的平移距离，用于校准left值
  },

  onMainPageTouchstart: function(e) {
    var data = this.drawerMenuMoveData;
    var clientX = e.touches[0].clientX;
    //初识状态
    if (data.state === 0) {
      if (clientX <= data.touchCheckX && clientX > 20) {
        data.check = true;
        data.state = 1;
        data.firstTouchX = clientX;
      }
    }
    //菜单弹出状态
    else if (data.state === 3) {
      if (clientX >= data.maxMoveX) {
        data.check = true;
        data.state = 2;
        data.firstTouchX = clientX;
      }
    } 
  },

  onMainPageTouchmove: function(e) {
    var data = this.drawerMenuMoveData;
    var pixelRatio = app.globalData.deviceInfo.pixelRatio;
    if (data.check) {
      var mainPageLeft = 0, drawerMenuLeft = 0;
      var moveX = e.touches[0].clientX - data.firstTouchX;
      if (data.state === 1)
      {
        //处理边界状态
        if (moveX < 0) {
          moveX = 0;
        }
        if (moveX > data.maxMoveX) {
          moveX = data.maxMoveX;
        }
        if (moveX >= 0 && moveX <= data.maxMoveX) {
          data.moveX = moveX;
          moveX = moveX - data.lastTranlateX;
          //px转为rpx
          moveX = moveX * pixelRatio;
          mainPageLeft = moveX;
          drawerMenuLeft = -800 + moveX;
        }
      }
      else if (data.state === 2) {
        //处理边界状态
        if (moveX > 0) {
          moveX = 0;
        }
        if (moveX < -data.maxMoveX) {
          moveX = -data.maxMoveX; 
        }
        if (moveX <= 0 && moveX >= -data.maxMoveX) {
          data.moveX = moveX;
          moveX = moveX - data.lastTranlateX;
          //px转为rpx
          moveX = moveX * pixelRatio;
          var maxMoveX = data.maxMoveX * pixelRatio;
          mainPageLeft = maxMoveX + moveX;
          drawerMenuLeft = maxMoveX -800 + moveX;
        }
      }

      this.setData({mainPageLeft: mainPageLeft, 
                    drawerMenuLeft: drawerMenuLeft});
    }
  },

 onMainPageTouchend: function(e) {
    var data = this.drawerMenuMoveData;
    if (!data.check) {
      return;
    }
    data.check = false;
    data.firstTouchX = 0;
    var moveX = data.moveX;
    data.moveX = 0;
    var animation = wx.createAnimation({duration: 100});
    var translateX = 0;
    var mainPageLeft = 0;
    var windowWidth = app.globalData.deviceInfo.windowWidth;
    if (data.state === 1)
    {
      if (moveX === 0 || moveX === data.maxMoveX) {
        data.state = (moveX === 0) ? 0 : 3;
        return;
      }
      mainPageLeft = moveX;
      //滑动距离是否超过窗口宽度一半
      if (mainPageLeft > (windowWidth / 2)) {
        translateX = data.maxMoveX - moveX;
        data.state = 3;
      }
      else {
        translateX = -moveX;
        data.state = 0;
      }
    } 
    else if (data.state === 2) {
      if (moveX === 0 || moveX === -data.maxMoveX) {
        data.state = (moveX === 0) ? 3 : 0;
        return;
      }
      //滑动距离是否超过窗口宽度一半
      mainPageLeft = data.maxMoveX + moveX
      if (mainPageLeft > (windowWidth / 2)) {
        translateX = -moveX;
        data.state = 3;
      }
      else {
        translateX = -mainPageLeft;
        data.state = 0;
      }
    }
    translateX += data.lastTranlateX;
    data.lastTranlateX = translateX;
    animation.translateX(translateX).step();
    this.setData({
      animationData:animation.export()
    });
  },

  onMainPageTap: function(e) {
    var data = this.drawerMenuMoveData;
    if (data.state !== 3) {
      return;
    }
    data.state = 0;
    var translateX = -data.maxMoveX;
    translateX += data.lastTranlateX;
    data.lastTranlateX = translateX;
    var animation = wx.createAnimation({duration: 100});
    animation.translateX(translateX).step();
    this.setData({
      animationData:animation.export()
    });
  }