鸿蒙Js实战，计算器功能开发-编程知识

场景：

通过动态设置按钮组件button实现计算器的键盘，通过文本text显示计算的表达书，可以计算+，-，*，/，可以一个一个移除，可以重置等。

下面我们开始今天的文章，还是老规矩，通过如下几点来说：

1，实现思路

2，代码解析

3，实现效果

3，总结

一，实现思路

计算器的键盘，本来是想使用grid的但是有一些默认属性不好控制，等后续组件完善了在做优化，目前grid适合一些均衡布局，通过监听计算符号添加判断逻辑，计算结果也是通过添加的计算类型进行计算，目前支持一级计算，后面做连续计算。

二，代码解析

子组件：

1，hml文件

实用了四个for循环实现了键盘效果，后面想了一下其实一个就能搞定，动态换行就行，时间有限后续优化(总感觉计算器挺简单，其实做起来还需要点时间)

<div class="container"><text class="input-content">{{inputcontent}}</text><div class="menu-content"><div class="caluater" for="{{ caluater }}" ><button class="content" onclick="calculatorClick({{ $item.id }})">{{ $item.id }}</button></div></div><div class="menu-content"><div class="caluater" for="{{ caluater1 }}"><button class="content2" on:click="calculatorClick({{ $item.id }})">{{ $item.id }}</button></div></div><div class="menu-content"><div class="caluater" for="{{ caluater2 }}"><button class="content2" on:click="calculatorClick({{ $item.id }})">{{ $item.id }}</button></div></div><div class="list2-content"><div class="list3-content"><div class="list2-content"><div class="caluater" for="{{ caluater3 }}"><button class="content2" on:click="calculatorClick({{ $item.id }})">{{ $item.id }}</button></div></div><div class="list2-content"><div class="caluater" for="{{ caluater4 }}"><button class="content2" on:click="calculatorClick({{ $item.id }})">{{ $item.id }}</button></div></div></div><button class="equals" onclick="calculatorResult">=</button></div>
</div>

2，css文件

样式比较简单，主要控制键盘和表达式文本的颜色和大小

.container {flex-direction: column;justify-content: flex-end;align-items: flex-end;width: 100%;
}
.input-content{background-color: #00ffffff;text-align: right;font-size: 25px;padding: 10px;font-weight: bold;
}
.menu-content{width: 100%;background-color: brown;allow-scale: true;
}
.caluater {flex-direction: row;width: 100%;height: 70px;background-color: #00ffffff;margin-left: 5px;margin-right: 5px;margin-top: 10px;
}
.content{font-size: 30px;font-weight: bold;radius: 10px;width: 100%;height: 100%;text-color: #007EFF;background-color: #A8CCFB;
}
.content2{font-size: 30px;font-weight: bold;radius: 10px;width: 100%;height: 100%;text-color: #000000;background-color: #dddcdc;
}
.list2-content{flex-direction: row;justify-content: center;align-items: center;background-color: brown;
}
.list3-content{flex-direction: column;margin-bottom: 10px;
}
.equals{width: 30%;height: 150px;font-size: 30px;font-weight: bold;radius: 10px;margin-left: 5px;margin-right: 5px;
}

3，js文件

js中主要实现逻辑，请看具体计算的判断。

import prompt from '@system.prompt';
export default {data: {title: "",inputcontent: "",number1: "",number2: "",type: "",caluater: [{'id': "C",},{'id': "÷",},{'id': "×",},{'id': "←",}],caluater1:[{'id': "7",},{'id': "8",},{'id': "9",},{'id': "+",}],caluater2:[{'id': "4",},{'id': "5",},{'id': "6",},{'id': "-",}],caluater3:[{'id': "1",},{'id': "2",},{'id': "3",}],caluater4:[{'id': "%",},{'id': "0",},{'id': ".",}]},onInit() {},calculatorClick(result){this.inputcontent = this.inputcontent+"";let str = this.inputcontent.substring(this.inputcontent.length-1, this.inputcontent.length);switch(result) {case "←":if(this.inputcontent.length > 0) {let str = this.inputcontent.substring(0, this.inputcontent.length - 1);this.inputcontent = str;}break;case "C":this.inputcontent = "";break;case "+":this.calcula(str,result,"+");break;case "-":this.calcula(str,result,"-");break;case "×":this.calcula(str,result,"×");break;case "÷":this.calcula(str,result,"÷");break;case ".":if(this.inputcontent.length > 0 && str != ".") {this.inputcontent += result;}break;default:this.inputcontent += result;break;}},calcula(str,result,cla){if(this.inputcontent.length > 0 && str != "+" && str != "-" && str != "×" && str != "÷") {this.type = cla;this.inputcontent += result;} else {this.calculatorResult();}},calculatorResult(){// 计算结果var temp = this.inputcontent.split(this.type);console.log("this.inputcontent = "+this.inputcontent)let str = this.inputcontent.substring(this.inputcontent.length-1, this.inputcontent.length);console.log("this.type = "+this.type)if (this.type == "+") {  // 加法计算if(temp.length > 1) {console.log("temp = "+temp)var num1 = parseFloat(temp[0]);var num2 = parseFloat(temp[1]);console.log("num1 = "+num1)console.log("num2 = "+num2)console.log("str = "+str)if(str != "+") {this.inputcontent = num1 + num2;this.type = "";}}} else if(this.type == "-") {  // 减法计算if(temp.length > 1) {var num1 = parseFloat(temp[0]);var num2 = parseFloat(temp[1]);if(str != "-") {this.inputcontent = num1 - num2;this.type = "";}}} else if(this.type == "×") {  // 乘法计算if(temp.length > 1) {var num1 = parseFloat(temp[0]);var num2 = parseFloat(temp[1]);if(str != "×") {this.inputcontent = num1 * num2;this.type = "";}}} else if(this.type == "÷") {  // 除法计算if(temp.length > 1) {var num1 = parseFloat(temp[0]);var num2 = parseFloat(temp[1]);if(str != "÷") {this.inputcontent = num1 / num2;this.type = "";}}}}
}