挂起函数“callGetApi”只能从协程或另一个挂起函数调用

我正在从 onCreate(...) 调用挂起函数

override fun onCreate(savedInstanceState: Bundle?) {
    ...
    ...
    callGetApi()
}

暂停的功能是：-

suspend fun callGetApi() {....}

但错误出现了挂起函数“callGetApi”只能从协程或另一个挂起函数调用

挂起函数只能从协程中调用。

这意味着调用一个suspend您需要使用的功能协程构建器 https://kt.academy/article/cc-builders, e.g. launch, async or runBlocking（建议仅在单元测试中使用）。例如：

class Activity : AppCompatActivity(), CoroutineScope {
    private var job: Job = Job()

    override val coroutineContext: CoroutineContext
        get() = Dispatchers.Main + job

    override fun onDestroy() {
        super.onDestroy()
        job.cancel()
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        launch {
            val result =  callGetApi()
            onResult(result) // onResult is called on the main thread
        }
    }

    suspend fun callGetApi(): String {...}

    fun onResult(result: String) {...}
}

To use Dispatchers.Main在 Android 中添加对应用程序的依赖build.gradle file:

implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.0.1'

The 最近的方法将使用扩展属性ViewModel and Activity/Fragment:

• In ViewModel https://developer.android.com/topic/libraries/architecture/viewmodel我们可以用viewModelScope https://developer.android.com/topic/libraries/architecture/coroutines#viewmodelscope启动协程：

  viewModelScope.launch { ... }
  

它附加到生命周期Activity/Fragment并在销毁时取消启动的协程。

• 类似的Activity/Fragment我们可以使用以下扩展属性来启动协程：lifecycleScope.launch {} https://developer.android.google.cn/reference/kotlin/androidx/lifecycle/package-summary#lifecyclescope, lifecycle.coroutineScope.launch {} https://developer.android.com/topic/libraries/architecture/coroutines#lifecyclescope, viewLifecycleOwner.lifecycleScope.launch {} https://developer.android.com/topic/libraries/architecture/coroutines#lifecyclescope（适用于Fragments).