微信小程序离线表单提交：如何实现离线填写表单并在网络恢复后自动提交？

{
  "pages": ["pages/formpage/formpage"],
  "window": {
    "backgroundtextstyle": "light",
    "navigationbarbackgroundcolor": "#fff",
    "navigationbartitletext": "离线表单",
    "navigationbartextstyle": "black"
  },
  "networkTimeout": {
    "request": 10000,
    "downloadFile": 10000
  },
  "debug": true
}

<!--  此处添加你的表单元素，例如input, textarea等 -->
<button bindtap="submitform">提交</button>

Page({
  data: {
    formData: {}
  },
  submitform: function(e) {
    const formData = e.detail.value;
    this.saveFormData(formData);
    this.checkNetworkAndSubmit();
  },
  saveFormData: function(formData) {
    wx.setStorageSync('formData', formData);
  },
  checkNetworkAndSubmit: function() {
    const that = this;
    wx.getNetworkType({
      success: function(res) {
        if (res.networkType !== 'none') {
          that.submitFormData();
        } else {
          console.log('网络不可用，数据已保存，等待网络恢复后自动提交');
        }
      }
    });
  },
  submitFormData: function() {
    const formData = wx.getStorageSync('formData');
    wx.request({
      url: '你的服务器接口地址',
      method: 'POST',
      data: formData,
      success: function(res) {
        console.log('提交成功');
        wx.removeStorageSync('formData');
      },
      fail: function(res) {
        console.error('提交失败', res);
        //  此处可添加重试逻辑
      }
    });
  }
});

App({
  onLaunch: function() {
    const that = this;
    wx.onNetworkStatusChange(function(res) {
      if (res.isConnected) {
        const formData = wx.getStorageSync('formData');
        if (formData) {
          that.submitFormData(formData);
        }
      }
    });
  },
  submitFormData: function(formData) {
    //  与pages/formPage/formPage.js中的submitFormData函数相同
  }
});