android - 无法从 Kotlin Android 中解析的 Json 数据为 TextView 赋值

Question

我有一个 textView，我想在其中存储来自 API 的数据。以下是我的代码

import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.widget.Button
import android.widget.TextView
import com.google.gson.GsonBuilder
import okhttp3.*
import java.io.IOException


class MainActivity : AppCompatActivity() {


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val btnFindIp = findViewById<Button>(R.id.btnFindIp)
        val txtIP = findViewById<TextView>(R.id.txtIP)

        btnFindIp.setOnClickListener {
            fetchJsonData()
        }


    } //onCreate Ends here


    fun fetchJsonData() {
        val url = "https://ipapi.co/json/"
        val request = Request.Builder().url(url).build()
        val httpClient = OkHttpClient()
        val txtIP = findViewById<TextView>(R.id.txtIP)



        httpClient.newCall(request).enqueue(object : Callback {
            override fun onFailure(call: Call?, e: IOException?) {
                println("Failed to execute")
            }

            override fun onResponse(call: Call?, response: Response?) {
                val body = response?.body()?.string()
                val gson = GsonBuilder().create()
                val ipData:Ip  = gson.fromJson(body, Ip::class.java)
//                txtIP.text = ipData.ip.toString()
                println(ipData.country_name)

              txtIP.text =  ipData.ip

            }
        })


    }


    data class Ip(
            val ip: String,
            val city: String,
            val region: String,
            val region_code: Any,
            val country: String,
            val country_name: String,
            val continent_code: String,
            val in_eu: Boolean,
            val postal: Any,
            val latitude: Double,
            val longitude: Double,
            val timezone: Any,
            val utc_offset: Any,
            val country_calling_code: String,
            val currency: String,
            val languages: String,
            val asn: String,
            val org: String
    )

}

我成功地从 API 获取数据并将其解析为 Data 类

 println(ipData.country_name)

这给出了正确的输出，但是当我将数据类值分配给 txtIP.text = ipData.ip 时，什么也没有发生，我确定我错过了一些东西，因为我对 Android 以及 Kotlin

非常感谢任何帮助

Answer 1

您不能从其他线程编辑 UI。自 documentation OkHTTP 说:

The recipient of the callback may consume the response body on another thread.

你必须这样设置文本:

runOnUiThread {txtIP.text = ipData.ip }