微信小程序用户点击按钮生成带参二维码的示例代码

<image class="scanimg" src="{{filePath}}" bindtap="getAgain"></image>
<button type="primary" bindtap="primary">点击生成二维码</button>

primary:function (e) {
var _url = '后台地址';
  wx.request({
    url: _url,
//请求报文体
    data: [{
      id: agentCode
    }],
    method: 'POST',
    header: {
      'content-type': 'application/json'
    },
    success: function (res) {
//为00时表示成功，得到二维码的地址
      if (res.data.code == '00') {
        console.log("成功")
//下载二维码
        wx.downloadFile({
          url: res.data.body[0].URL,
          success: function (res) {
//如果二维码中的id为固定值可以将图片保存到本地，否则不用保存
            wx.saveFile({
              tempFilePath: res.tempFilePath,
              success: function (res) {
                console.log("保存成功")
_that.setData({
filePath: res.savedFilePath
})
console.log(res.savedFilePath)
try {
//id为定值，则将保存的地址存入缓存，非定值则只需要setData就行
wx.setStorageSync('filePath', res.savedFilePath)
} catch (e) {
console.log(e)
}
              },
              fail: function (res) {
                console.log("保存失败")
                console.log(res)
              }
            })
          }, fail: function (res) {
            util.msg("错误", "通讯失败")
            console.log(res)
          }
        })
      } else {
        console.log("错误")
        util.msg("错误", res.data.msg)
      }
    },
    fail: function () {
      util.msg("错误", "通讯失败")
      console.log(res)
    }
  })
}

// 访问微信后台的URL
String URL = systemConfig.getString("LoginOrRegisterUrl");
// 请求类型
String grant_type = systemConfig.getString("grant_type");
// 第三方用户唯一凭证密钥
String secret = systemConfig.getString("secret");
// 第三方用户唯一凭证
String appId = systemConfig.getString("appid");
// 请求token时用到的URL
String tokenUrl = systemConfig.getString("tokenUrl");
// 向微信后台请求获取token
                        String sendGet = HttpClientConnectionManager.sendGet(
                                tokenUrl, "grant_type=" + grant_type
                                        + "&secret=" + secret + "&appid="
                                        + appId + "");
                        System.out.println(sendGet);
                        JSONObject json = JSONObject.fromObject(sendGet);
                        access_token = json.get("access_token").toString();
                        if (access_token == null) {
//没有token 则返回错误码和错误信息
                            agentDTO.setCode("0002");
                            agentDTO.setDesc("获取tokenId失败");
                            return agentDTO;
                        }
System.out.println(access_token);
// 访问微信后台带的json参数
                    Map<String, Object> map = new HashMap<String, Object>();
                    map.put("path", "pages/register");//你二维码中跳向的地址
                    map.put("width", "430");//图片大小
                    JSONObject json = JSONObject.fromObject(map);
                    HttpClientConnectionManager.httpPostWithJSON(URL
                            + access_token, json.toString(), id + "max");
                    // 返回给前端的后台服务器文件读取路径
                    String downloadUrl = systemConfig
                            .getString("agentImgDownloadUrl")
                            + id
                            + "max"
                            + "/";
                    // 返回给前端的后台服务器文件下载路径
                    String downloadfileUrl = downloadUrl + id + "max" + ".jpg";
                    agentResView.setURL(downloadfileUrl);
                    agentDTO.setAgentResView(agentResView);
agentDTO.setCode("00");
agentDTO.setDesc("成功");
                        return agentDTO;