我这边登陆不上去

package com.example.isfishing.activity

import android.os.Bundle
import android.util.Log
import android.view.View
import android.widget.Button
import android.widget.EditText
import android.widget.ImageView
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import com.example.isfishing.R
import com.example.isfishing.api.Api
import okhttp3.*
import okhttp3.MediaType.Companion.toMediaTypeOrNull
import java.io.IOException


class LoginActivity : AppCompatActivity(), View.OnClickListener {
    private lateinit var et_phon: EditText
    private lateinit var et_yanzhengma: EditText
    private lateinit var tv_yz: TextView
    private lateinit var btn_login: Button
    private lateinit var iv_wx: ImageView

    //倒计时
    private var i = 60
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_login)
        initView()
    }

    private fun initView() {
        et_phon = findViewById(R.id.et_phon)
        et_yanzhengma = findViewById(R.id.et_yanzhengma)
        tv_yz = findViewById(R.id.bt_yz)
        btn_login = findViewById(R.id.btn_login)
        iv_wx = findViewById(R.id.iv_wx)

        //监听
        btn_login.setOnClickListener(this)
        iv_wx.setOnClickListener(this)
    }

    override fun onClick(v: View) {
        val phone = et_phon.text.toString().trim()
        val code = et_yanzhengma.text.toString().trim()
        when (v.id) {
            R.id.btn_login -> {//手机登陆
            }
            R.id.iv_wx -> {//微信登陆

            }
            R.id.bt_yz -> {//获取验证码
                Postcode(phone)
            }
        }
    }

    private fun Postcode(phone: String) {
        val url = Api.CODE
        val mediaType = "text/x-markdown; charset=utf-8".toMediaTypeOrNull()
        val requestBody: RequestBody = FormBody.Builder()
                .add("Mobile", phone)
                .add("MsgType", 2.toString())
                .build()
        val client = OkHttpClient()
        val request = Request.Builder()
                .url(url)
                .post(requestBody)
                .build()
        val newCall = client.newCall(request)
        newCall.enqueue(object : Callback {
            override fun onFailure(call: Call, e: IOException) {
                TODO("Not yet implemented")
            }

            override fun onResponse(call: Call, response: Response) {
                val body = response.body
            }

        })
    }
}