“Fatal exception with Kotlin Coroutine without proper error message”

huangapple
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英文:

Fatal exception with Kotlin Coroutine without proper error message

问题

我正在学习 Kotlin 协程，并尝试构建一个带有一些 API 请求的简单应用。不幸的是，我遇到了一个错误，这个错误没有提供详细信息，以下是日志中的全部内容：

  1. FATAL EXCEPTION: main
  2. Process: com.tests.myapp, PID: 14743

这是我的简单协程，它只是调用一个 API 端点。我从这个教程中复制了语法。

  1. CoroutineScope(Dispatchers.Main).launch {
  2.    API.call().registration();
  3. }

对于 Kotlin 协程，我使用的版本是：

  1. implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.6.4'

对于网络库，我使用的是 Retrofit，如下所示：

  1. object API {
  3.     private const val BASE_URL = "http://my-test-url-comes-here.com"
  5.     private val okHttpClient = OkHttpClient()
  6.         .newBuilder()
  7.         .addInterceptor(RequestInterceptor)
  8.         .build()
  10.     private fun getClient(): Retrofit =
  11.         Retrofit.Builder()
  12.             .client(okHttpClient)
  13.             .baseUrl(BASE_URL)
  14.             .addConverterFactory(GsonConverterFactory.create())
  15.             .build()
  17.     fun call(): Endpoints {
  18.         return  getClient().create(Endpoints::class.java)
  19.     }
  20. }

有什么见解吗？

英文:

I'm learning Kotlin Coroutines and I'm trying to build a simple app with some API requests.
Unfortunately I've stumbled upon an error which is not really talkative, this is all I have in the logs:

  1. FATAL EXCEPTION: main 
  2. Process: com.tests.myapp, PID: 14743

This is my simple coroutine which would simply call an API endpoint. I've copied the syntax from this tutorial.

  1.   CoroutineScope(Dispatchers.Main).launch {
  2.        API.call().registration();
  3.   }

For Kotlin Coroutines I use this version:

  1. implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.6.4'

And for the networking library I have Retrofit like this:

  1. object API {
  3.     private const val BASE_URL = "http://my-test-url-comes-here.com"
  5.     private val okHttpClient = OkHttpClient()
  6.         .newBuilder()
  7.         .addInterceptor(RequestInterceptor)
  8.         .build()
  10.     private fun getClient(): Retrofit =
  11.         Retrofit.Builder()
  12.             .client(okHttpClient)
  13.             .baseUrl(BASE_URL)
  14.             .addConverterFactory(GsonConverterFactory.create())
  15.             .build()
  18.     fun call(): Endpoints {
  19.       return  getClient().create(Endpoints::class.java)
  20.     }
  21. }

Any insights?

答案1

得分: 1

我认为你应该使用 Dispatchers.IO，因为你在调用一个使用网络的函数。通过传递 Dispatcher.Main，你正在要求协程作用域使用 UI 线程，这将导致主线程上的网络异常。

所以，你可以这样做：

  1.   CoroutineScope(Dispatchers.IO /* 在这里替换为 IO */).launch {
  2.        API.call().registration();
  3.   }
英文:

I think you should use Dispatchers.IO because you are calling a functon that uses network. by passing Dispatcher.Main, you are asking coroutinScope to use UI thread. that gives a Network on Main thread Exception.
so,

  1.   CoroutineScope(Dispatchers.IO /* replace Main with IO here */).launch {
  2.        API.call().registration();
  3.   }

答案2

得分: 0

尝试使用Dispatchers.IO，并建议您仅创建一次您的API服务，就像这样检查您的清单文件 - 您应该向您的应用程序添加Internet权限以进行网络调用。

  1. object API {
  3.     private const val BASE_URL = "http://my-test-url-comes-here.com"
  5.     private val okHttpClient = OkHttpClient()
  6.         .newBuilder()
  7.         .addInterceptor(RequestInterceptor)
  8.         .build()
  10.     private val client by lazy {
  11.         Retrofit.Builder()
  12.             .client(okHttpClient)
  13.             .baseUrl(BASE_URL)
  14.             .addConverterFactory(GsonConverterFactory.create())
  15.             .build()
  16.     }
  18.     val api by lazy {
  19.         client.create(Endpoints::class.java)
  20.     }
  22. }

注意：我在这里写的lazy初始化程序只是一个示例，您也可以使用非懒惰的初始化程序。

英文:

try to use Dispatchers.IO and also I would suggest you to create your api service only once like this and check you manifest file - you should add internet permission to your app, to make network calls

  1. object API {
  3.    private const val BASE_URL = "http://my-test-url-comes-here.com"
  5.    private val okHttpClient = OkHttpClient()
  6.       .newBuilder()
  7.       .addInterceptor(RequestInterceptor)
  8.       .build()
  10.    private val client by lazy {
  11.       Retrofit.Builder()
  12.           .client(okHttpClient)
  13.           .baseUrl(BASE_URL)
  14.           .addConverterFactory(GsonConverterFactory.create())
  15.           .build()
  16.    }
  19.     val api by lazy {
  20.        client.create(Endpoints::class.java)
  21.     }
  23. }

NOTE: the lazy initializer I wrote here is just sample you can also you non-lazy initializer

huangapple
  • 本文由 发表于 2023年2月14日 02:27:13
  • 转载请务必保留本文链接：https://go.coder-hub.com/75439876.html
  • android
  • kotlin
  • kotlin-coroutines
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