给我写一个微信小程序开发计算器案例完整代码

微信小程序的计算器是一个基础的小程序功能示例，这里提供一个简单的加减乘除功能的代码：

<!-- app.json -->
{
  "pages": [
    "index",
    "login",
    "settings"
  ],
  "window": {
    "backgroundTextStyle": "light",
    "navigationBarBackgroundColor": "#fff",
    "navigationBarTitleText": "Wechat Calculator",
    "navigationBarTextStyle": "black"
  }
}

<!-- index.wxml -->
<view class="container">
  <button bindtap="clear">清空</button>
  <view class="calculator" wx:for="{{numbers}}" wx:key="*this">{{item}}</view>
  <input type="number" value="{{result}}" placeholder="请输入计算结果" />
  <button bindtap="add">+</button>
  <button bindtap="subtract">-</button>
  <button bindtap="multiply">*</button>
  <button bindtap="divide">/</button>
  <button bindtap="calculate">=</button>
</view>

<!-- index.wxss -->
.container {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.calculator {
  flex-direction: column;
  margin-bottom: 5px;
}

<!-- index.js -->
Page({
  data: {
    numbers: ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
    result: '',
    operation: ''
  },
  methods: {
    clear() {
      this.setData({
        numbers: [],
        result: '',
        operation: ''
      });
    },
    add() {
      if (this.data.operation === '+') {
        let sum = parseFloat(this.data.result) + parseFloat(numbers[this.data.numbers.length - 1]);
        this.setData({
          numbers: [...this.data.numbers, sum],
          result: sum.toString(),
          operation: ''
        });
      } else {
        this.setData({
          numbers: [this.data.result, ...this.data.numbers],
          result: '',
          operation: '+'
        });
      }
    },
    subtract() { ... },
    multiply() { ... },
    divide() { ... },
    calculate() { ... },
    // 其他运算方法类似，只是处理除法时需要防止除数为零
  }
})

这个代码展示了基本的界面结构和事件绑定，实际开发中还需要完善错误处理、输入验证等细节，并根据需求添加更多的运算操作。注意，在微信小程序开发环境中运行此代码。