kotlin 中的烧瓶 + 改造无法使用 IP 地址访问 API 端点（无法连接到 /127.0.0.1:5000）

Question

我在烧瓶中创建了一个 api，它返回经度、纬度和 id。我想在我自己的安卓设备中得到这个响应。我用邮递员测试了这个api，我也可以通过手机浏览器访问它
URL = "http://192.168.0.185:3000"

尝试通过改造来访问它会产生很长的错误轨迹，我无法弄清楚。

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.posttest, PID: 2144
    java.net.ConnectException: Failed to connect to /127.0.0.1:5000
        at okhttp3.internal.connection.RealConnection.connectSocket(RealConnection.kt:285)
        at okhttp3.internal.connection.RealConnection.connect(RealConnection.kt:195)
        at okhttp3.internal.connection.ExchangeFinder.findConnection(ExchangeFinder.kt:249)
        at okhttp3.internal.connection.ExchangeFinder.findHealthyConnection(ExchangeFinder.kt:108)
        at okhttp3.internal.connection.ExchangeFinder.find(ExchangeFinder.kt:76)
        at okhttp3.internal.connection.RealCall.initExchange$okhttp(RealCall.kt:245)
        at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.kt:32)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:100)
        at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.kt:82)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:100)
        at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.kt:83)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:100)
        at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.kt:76)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:100)
        at okhttp3.internal.connection.RealCall.getResponseWithInterceptorChain$okhttp(RealCall.kt:197)
        at okhttp3.internal.connection.RealCall$AsyncCall.run(RealCall.kt:502)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:919)
     Caused by: java.net.ConnectException: failed to connect to /127.0.0.1 (port 5000) from /127.0.0.1 (port 37738) after 10000ms: isConnected failed: ECONNREFUSED (Connection refused)

我尝试了在我的模拟器上运行应用程序然后尝试使用
URL ="http://10.0.2.2:3000"

访问它的方法

它仍然给我错误。我怎样才能做到这一点？这是我的 api 响应的样子：

我的 Flask 服务器代码很简单

app = Flask(__name__)
api = Api(app)
api.add_resource(LocationValues, '/adamapi')

@app.route('/')
def hello():
    return 'Hello,REST'

if __name__ == '__main__':
    app.run("0.0.0.0",debug=True,port= 3000)

Resource.py

    def get(self):
        connection = sqlite3.connect('db.sqlite')
        cursor = connection.cursor()
        query = "SELECT * FROM location WHERE id = 1"
        result = cursor.execute(query).fetchone()
        connection.close()
        if result:
            return {'item': {'measure_id': result[0], 'longitude': result[1], 'latitude': result[2]}}
        return {"message": "Wrong get request"}, 400

还有 Kotlin 文件
Contants.kt

class Constants {
    companion object{
        const val BASE_URL = "http://192.168.0.185:3000"
    }
}

DataClass.kt

data class Post(
    val item: Item
)

data class Item(
    val latitude: Double,
    val longitude: Double,
    val measure_id: Int
)

SimpleApi.kt

interface SimpleApi {
    @GET("adamapi")
    suspend fun getPost(): Post
}

Repository.kt

class Repository {
    suspend fun getPost(): Post {
        return RetrofitInstance.api.getPost()

    }
}

RetrofitInstance.kt

object RetrofitInstance {

    private val retrofit  by lazy {
        Retrofit.Builder()
            .baseUrl(BASE_URL)
            .addConverterFactory(GsonConverterFactory.create())
            .build()

    }
    val api:SimpleApi by lazy {
        retrofit.create(SimpleApi::class.java)
    }
}

MainViewModel and MainViewModelFactory classes in .kt

class MainViewModel(private  val repository: Repository):ViewModel() {
    val myResponse: MutableLiveData<Post> = MutableLiveData()
    fun getPost (){
        viewModelScope.launch {
            val response :Post = repository.getPost()
            myResponse.value = response
        }
    }
}


class MainViewModelFactory (private val repository:Repository):ViewModelProvider.Factory {
    override fun <T: ViewModel?> create (modelClass: Class<T>):T{
        return MainViewModel(repository) as T
    }
}

我在 Manifest 文件中添加了 Internet 权限。此外，这里的解释也不适用于我的设备-> https://medium.com/analytics-vidhya/how-to-make-client-android-application-with-flask-for-server-side-8b1d5c55446e
我的两台设备都在使用 Wifi。

错误：

更新：按照@martin-zeitler 的回答它现在可以在模拟器上运行。但是使用我的 ipv4 地址仍然会出错。

Answer 1

在 RetrofitInstance.kt 中，在 BASE_URL 之后添加“/”，所以它看起来像这样：

private val retrofit  by lazy {
    Retrofit.Builder()
        .baseUrl(BASE_URL + "/")
        .addConverterFactory(GsonConverterFactory.create())
        .build()

}

Answer 2

堆栈跟踪显然与代码不匹配。

当打算连接到一个 IP 地址时，应该说明它：

companion object {
    const val BASE_URL = "http://10.0.2.2:3000/"
}

然后在src/debug/res/xml/network_security_config.xml添加备用配置：

<?xml version="1.0" encoding="utf-8"?>
<!-- Debug Network Security Configuration -->
<network-security-config
    xmlns:tools="http://schemas.android.com/tools">
    <base-config
        tools:ignore="InsecureBaseConfiguration"
        cleartextTrafficPermitted="true">
        <trust-anchors>
            <certificates src="system"/>
        </trust-anchors>
    </base-config>
</network-security-config>

还要引用AndroidManifest.xml：

<application
    ...
    android:networkSecurityConfig="@xml/network_security_config" />

这是在调试时允许纯文本 HTTP 流量所必需的。