微信小程序开发简易计算器改进版

微信小程序开发计算器有多种方法，但是大部分代码比较复杂、不容易理解。本案例进行了改进，主要是组件bindtap属性绑定的自定义函数clickBtn()，采用了switch语句，使得代码结构更加清晰，学习者更容易理解，现分享如下。案例的效果如下图所示：

制作步骤如下：

1. 在微信开发者工具的全局控制app.json文件pages数组中输入“pages/calculator/calcu”，建立计算器页面相关文件，在window属性中更改导航标题为“简单计算器”。app.json的代码如下：

{

"pages":[

"pages/calculator/calcu",

"pages/index/index",

"pages/logs/logs"

],

"window":{

"backgroundTextStyle":"light",

"navigationBarBackgroundColor": "#fff",

"navigationBarTitleText": "简单计算器",

"navigationBarTextStyle":"black"

}

}

2. 页面布局文件calcu.wxml的代码如下：

<view class='content'>

<view class='scr'>

{{screenData}}

</view>

<view class='btnGroup'>

<view class='item gray' bindtap='clickBtn' id='{{b01}}'>←</view>

<view class='item gray' bindtap='clickBtn' id='{{b02}}'>C </view>

<view class='item gray' bindtap='clickBtn' id='{{b03}}'> +/- </view>

<view class='item gray' bindtap='clickBtn' id='{{b04}}'>+</view>

</view>

<view class='btnGroup'>

<view class='item gray' bindtap='clickBtn' id='{{b05}}'> 9</view>

<view class='item gray' bindtap='clickBtn' id='{{b06}}'> 8 </view>

<view class='item gray' bindtap='clickBtn' id='{{b07}}'> 7 </view>

<view class='item gray' bindtap='clickBtn' id='{{b08}}'>-</view>

</view>

<view class='btnGroup'>

<view class='item gray' bindtap='clickBtn' id='{{b09}}'> 6</view>

<view class='item gray' bindtap='clickBtn' id='{{b10}}'> 5 </view>

<view class='item gray' bindtap='clickBtn' id='{{b11}}'> 4 </view>

<view class='item gray' bindtap='clickBtn' id='{{b12}}'>×</view>

</view>

<view class='btnGroup'>

<view class='item gray' bindtap='clickBtn' id='{{b13}}'> 3</view>

<view class='item gray' bindtap='clickBtn' id='{{b14}}'> 2 </view>

<view class='item gray' bindtap='clickBtn' id='{{b15}}'> 1</view>

<view class='item gray' bindtap='clickBtn' id='{{b16}}'>÷</view>

</view>

<view class='btnGroup'>

<view class='item gray'bindtap='clickBtn' id='{{b17}}' > 0</view>

<view class='item gray'bindtap='clickBtn' id='{{b18}}'> . </view>

<view class='item gray'bindtap='getSqrt' id='{{b19}}'> √</view>

<view class='item orange'bindtap='clickBtn' id='{{b20}}'>=</view>

</view>

</view>

3. 页面样式文件calcu.wxss的代码如下：

/* */

.content{

height:100%;

display: flex;

flex-direction: column;

align-items:center;

box-sizing: border-box;

background:#555;

padding:30rpx 0 20rpx 0;

}

.scr{

background:#fff;

width:700rpx;

height: 100rpx;

line-height: 100rpx;

text-align: right;

margin:0 0 10rpx 0;

padding:0 10rpx 0 0;

font-size:30px;

}

.btnGroup{

display: flex;

flex-direction: row;

}

.item{

width:175rpx;

min-height: 150rpx;

margin: 1rpx;

text-shadow:0 1px 1px rgba(255,255,255,.3);

text-align: center;

line-height: 150rpx;

}

.gray{

background:#eee;

}

.orange{

color:#fff;

background:#f60;

}

4.逻辑处理文件calcu.js的代码如下：

Page({

data: {

b01:"back",

b02: "clear",

b03: "negative",

b04: "+",

b05: "9",

b06: "8",

b07: "7",

b08: "-",

b09: "6",

b10: "5",

b11: "4",

b12: "×",

b13: "3",

b14: "2",

b15: "1",

b16: "÷",

b17: "0",

b18: ".",

b19: "sqrt",

b20: "=" ,

screenData:"0",

lastOperator:false,

arr:[],

logs:[]

},

clickBtn: function (event) {

console.log(event.target.id);

var id = event.target.id;

switch (id) {

case "back":

//退格

var data = this.data.screenData;

if (data == 0) {

return;

}

data = data.substring(0, data.length - 1);

if (data == "" || data == "-") {

data = 0;

}

this.setData({

screenData: data

});

this.data.arr.pop();

break;

case "clear":

//清屏

this.setData({

screenData: "0"

});

this.data.arr.length = 0;

break;

case "negative":

//正负号

var data = this.data.screenData;

if (data == 0) {

return;

}

var firstword = data.substring(0, 1);

if (firstword == "-") {

data = data.substring(1, data.length);

this.data.arr.shift();

} else {

data = "-" + data;

this.data.arr.unshift("-");

}

this.setData({

screenData: data

});

break;

case "=":

//等号=

var data = this.data.screenData;

if (data == 0) {

return;

}

var lastWord = data.substring(data.length - 1, data.length);

if (isNaN(lastWord)) {

return;

}

var num = "";

var lastOperator;

var arr = this.data.arr;

var optarr = [];

for (var i in arr) {

if (isNaN(arr[i]) == false || arr[i] == this.data.b18 || arr[i] == this.data.b03) {

num += arr[i];

} else {

lastOperator = arr[i];

optarr.push(num);

optarr.push(arr[i]);

num = "";

}

}

optarr.push(Number(num));

var result = Number(optarr[0]) * 1.0;

console.log(result);

for (var i = 1; i < optarr.length; i++) {

if (isNaN(optarr[i])) {

if (optarr[1] == this.data.b04) {

result += Number(optarr[i + 1]);

} else if (optarr[1] == this.data.b08) {

result -= Number(optarr[i + 1]);

} else if (optarr[1] == this.data.b12) {

result *= Number(optarr[i + 1]);

} else if (optarr[1] == this.data.b16) {

result /= Number(optarr[i + 1]);

}

}

}

//

this.data.arr.length = 0;

this.data.arr.push(result);

this.setData({

screenData: result + ""

});

break;

default:

if (id == this.data.b04 || id == this.data.b08 || id == this.data.b12 || id == this.data.b16) {

if (this.data.lastOperator == true || this.data.screenData == 0) {

return;

}

}

var num = this.data.screenData;

var data;

if (num == 0) {

data = id;

} else {

data = num + id;

}

this.setData({

screenData: data

});

this.data.arr.push(id);

if (id == this.data.b04 || id == this.data.b08 || id == this.data.b12 || id == this.data.b16) {

this.setData({

lastOperator: true

});

} else {

this.setData({

lastOperator: false

});

}

break;

}

},

getSqrt: function () {

//平方根

var data = Math.sqrt(this.data.screenData);

this.setData({

screenData: data

});

}

})

5. 至此，案例制作完成，希望对大家的学习有很好的帮助。