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最近在学习Vue的指令,做了一个简易计算器,比较适合刚入门的人参考学习。用到的知识点有:
1.插值表达式
2.v-model,双向绑定+、-、*、/、**等操作符
3.v-show,控制操作数2是否显示,乘方时不显示操作数2
4.methods选项,定义了calculate ()方法,实现各种运算
5.watch选项,监听selected的值的变化。
下面是程序的执行效果:
如果选择的是**乘方,操作数2不显示,这是利用v-show控制实现的,如图所示。
参考代码如下。
<!DOCTYPE html>
<html>
<head><title>项目2-1简易计算器</title><script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
</head>
<body><div id="app"><div class="calc"><h3>简易计算器</h3><p> 操作数1 <input type="number" v-model="oper1" class="operand" /></p><p class="opera"> 运算符<input type="radio" name="operator" value="+" v-model="selected">+<input type="radio" name="operator" value="-" v-model="selected">-<input type="radio" name="operator" value="*" v-model="selected">x<input type="radio" name="operator" value="/" v-model="selected">➗<input type="radio" name="operator" value="**" v-model="selected">**</p><p><span v-show="isSeen">操作数2 <input type="number" v-model="oper2" class="operand" /></span></p><p> <button @click="calculate">计算=</button></p><div><div class="fs22">结果:{{result}}</div></div></div></div>
</body>
<script type="text/javascript">const RootComponent = { //创建根组件data() {return {isSeen: true,selected: '',oper1: '',oper2: '',result: '',}},methods: {calculate () {if (this.selected === '') {alert("请选择运算符")return}switch (this.selected) {case "+":this.result = this.oper1 + this.oper2breakcase "-":this.result = this.oper1 - this.oper2breakcase "*":this.result = this.oper1 * this.oper2breakcase "/":this.result = (this.oper1 / this.oper2).toFixed(2)breakcase "**":this.result = this.oper1 * this.oper1break}}},watch: {selected(newValue, oldValue) {if (newValue === "**") {this.isSeen = false} else {this.isSeen = true}}}}//创建Vue应用实例并挂载到#appconst vueApp = Vue.createApp(RootComponent) vueApp.mount("#app")
</script>
<style>.calc {width: 600px;margin: 0 auto;}.operand {width: 120px;height: 30px;font-size: 20px;}.opera input {margin-left: 20px;}button {width: 80px;height: 40px;background-color: #339f63;color: #fff;font-size: 18px;border-color: #ccc;border-radius: 5px;}.fs22 {font-size: 22px;color: red;}
</style>
</html>
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