离子/角 HTTP 发布请求不适用于 android

Question

I used Angular HTTP while testing in the browser and it worked fine, but it doesn't on an actual mobile device... Apparently HTTP angular doesn't work on mobile and I had to convert the post request to ionic native HTTP. 我不确定它是否正确转换以及问题是什么......
此外，获取请求工作正常只是发布请求不起作用。
希望有人可以帮助我。
提前致谢！

我的代码：
angular HTTP 发布请求

senduserdata(username){
    var dataToSend = {
      username:this.Username,
      password:this.Password,
      usertype:this.getSelectedSubject,
    }

    var url = 'https://mylink.herokuapp.com/login';

    this.http.post(url,{data:JSON.stringify(dataToSend)},{responseType: 'text'}).subscribe(
      (data)=>{
        alert(data);
        if(data === "Logged In Successfully!")
        {
          this.LoginCustomer();
          this.cartservice.setUsernameCustomer(this.Username);
        }
        else if(data === "Welcome!")
        {
          this.LoginStaff();
          this.cartservice.setUsernameStaff(this.Username);
        }
      }
    ) 
  }

离子高级 HTTP 发布请求

senduserdata(){
    var dataToSend = {
      username:this.Username,
      password:this.Password,
      usertype:this.getSelectedSubject,
    }

    var url = 'https://mylink.herokuapp.com/login';

    this.http.post(url,{data:JSON.stringify(dataToSend)},{responseType: 'text'}).then(
      (data)=>{
        this.message= JSON.parse(data.data);
        alert(this.message)
    
        if(this.message === "Logged In Successfully!")
        {
          this.LoginCustomer();
          this.cartservice.setUsernameCustomer(this.Username);
        }
        else if(this.message === "Welcome!")
        {
          this.LoginStaff();
          this.cartservice.setUsernameStaff(this.Username);
        }
      }
    ) 
  }

Answer 1

更新
原来它适用于浏览器，因为我使用的是 CORS 转换器扩展，
我只需要添加我的 node.js 文件

app.all('*', function(req, res, next) {
    var origin = req.get('origin'); 
    res.header('Access-Control-Allow-Origin', origin);
    res.header("Access-Control-Allow-Headers", "X-Requested-With");
    res.header('Access-Control-Allow-Headers', 'Content-Type');
    next();
});

var app = express();
var cors = require('cors');
app.use(cors())