自己的第一个点餐小程序，主要包括左右菜单联动、点击数量加减、菜单和购物车数量可以同步加减、购物车动画等，纯前端实现

大致的功能样式如下图展示：

代码块

主要代码块：

// 点击左侧分类切换右侧菜品

changeRightMenu: function (e) {

var classify = e.target.dataset.id;// 获取点击项的id

var foodList = this.data.foodList;

var allFoodList = this.data.allFoodList;

var newFoodList = [];

if (classify == 0) {//选择了全部选项

this.setData({

curNav: classify,

foodList: allFoodList

})

} else { //选择了其他选项

for (var i in allFoodList) {

if (allFoodList[i].catid == classify) {

newFoodList.push(allFoodList[i])

}

}

this.setData({

// 右侧菜单当前显示第curNav项

curNav: classify,

foodList: newFoodList

})

}

},

// 购物车及菜单中增加数量

addCount: function (e) {

var id = e.currentTarget.dataset.id;[这里写链接内容](http://download.csdn.net/download/m0_37543652/10019843%20%20%E6%BA%90%E7%A0%81%E4%B8%8B%E8%BD%BD%E5%9C%B0%E5%9D%80)

var arr = wx.getStorageSync('cart') || [];

var f = false;

for (var i in this.data.foodList) {// 遍历菜单找到被点击的菜品，数量加1

if (this.data.foodList[i].id == id) {

this.data.foodList[i].quantity += 1;

if (arr.length > 0) {

for (var j in arr) {// 遍历购物车找到被点击的菜品，数量加1

if (arr[j].id == id) {

arr[j].quantity += 1;

f = true;

try {

wx.setStorageSync('cart', arr)

} catch (e) {

console.log(e)

}

break;

}

}

if (!f) {

arr.push(this.data.foodList[i]);

}

} else {

arr.push(this.data.foodList[i]);

}

try {

wx.setStorageSync('cart', arr)

} catch (e) {

console.log(e)

}

break;

}

}

this.setData({

cartList: arr,

foodList: this.data.foodList

})

this.getTotalPrice();

},

// 定义根据id删除数组的方法

removeByValue: function (array, val) {

for (var i = 0; i < array.length; i++) {

if (array[i].id == val) {

array.splice(i, 1);

break;

}

}

},

// 购物车减少数量

minusCount: function (e) {

var id = e.currentTarget.dataset.id;

var arr = wx.getStorageSync('cart') || [];

for (var i in this.data.foodList) {

if (this.data.foodList[i].id == id) {

this.data.foodList[i].quantity -= 1;

if (this.data.foodList[i].quantity <= 0) {

this.data.foodList[i].quantity = 0;

}

if (arr.length > 0) {

for (var j in arr) {

if (arr[j].id == id) {

arr[j].quantity -= 1;

if (arr[j].quantity <= 0) {

this.removeByValue(arr, id)

}

if (arr.length <= 0) {

this.setData({

foodList: this.data.foodList,

cartList: [],

totalNum: 0,

totalPrice: 0,

})

this.cascadeDismiss()

}

try {

wx.setStorageSync('cart', arr)

} catch (e) {

console.log(e)

}

}

}

}

}

}

this.setData({

cartList: arr,

foodList: this.data.foodList

})

this.getTotalPrice();

},