鸿蒙Js实战，计算器功能开发

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 = "";
                }
            }
        }
    }
}