我已经在android studio中完成了开发react native app作为一项新活动，它在模拟器上工作正常，因为它使用了localhost服务器。现在我想在我的设备上运行这个应用程序，但它会抛出异常
E/unknown:React: IOException requesting status from packager java.net.ConnectException: failed to connect to localhost/127.0.0.1 (port 8081) after 5000ms: isConnected failed: ECONNREFUSED (Connection refused)
at libcore.io.IoBridge.isConnected(IoBridge.java:267)
at libcore.io.IoBridge.connectErrno(IoBridge.java:191)
at libcore.io.IoBridge.connect(IoBridge.java:127)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:461)
at java.net.Socket.connect(Socket.java:918)
at com.squareup.okhttp.internal.Platform$Android.connectSocket(Platform.java:190)
at com.squareup.okhttp.Connection.connectSocket(Connection.java:196)
at com.squareup.okhttp.Connection.connect(Connection.java:172)
at com.squareup.okhttp.Connection.connectAndSetOwner(Connection.java:367)
at com.squareup.okhttp.OkHttpClient$1.connectAndSetOwner(OkHttpClient.java:128)
at com.squareup.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:328)
at com.squareup.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:245)
at com.squareup.okhttp.Call.getResponse(Call.java:267)
at com.squareup.okhttp.Call$ApplicationInterceptorChain.proceed(Call.java:224)
at com.squareup.okhttp.Call.getResponseWithInterceptorChain(Call.java:195)
at com.squareup.okhttp.Call.access$100(Call.java:34)
at com.squareup.okhttp.Call$AsyncCall.execute(Call.java:162)
at com.squareup.okhttp.internal.NamedRunnable.run(NamedRunnable.java:33)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
Caused by: android.system.ErrnoException: isConnected failed: ECONNREFUSED (Connection refused)
at libcore.io.IoBridge.isConnected(IoBridge.java:252)
at libcore.io.IoBridge.connectErrno(IoBridge.java:191)
at libcore.io.IoBridge.connect(IoBridge.java:127)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:461)
at java.net.Socket.connect(Socket.java:918)
at com.squareup.okhttp.internal.Platform$Android.connectSocket(Platform.java:190)
at com.squareup.okhttp.Connection.connectSocket(Connection.java:196)
at com.squareup.okhttp.Connection.connect(Connection.java:172)
at com.squareup.okhttp.Connection.connectAndSetOwner(Connection.java:367)
at com.squareup.okhttp.OkHttpClient$1.connectAndSetOwner(OkHttpClient.java:128)
at com.squareup.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:328)
at com.squareup.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:245)
at com.squareup.okhttp.Call.getResponse(Call.java:267)
at com.squareup.okhttp.Call$ApplicationInterceptorChain.proceed(Call.java:224)
at com.squareup.okhttp.Call.getResponseWithInterceptorChain(Call.java:195)
at com.squareup.okhttp.Call.access$100(Call.java:34)
at com.squareup.okhttp.Call$AsyncCall.execute(Call.java:162)
at com.squareup.okhttp.internal.NamedRunnable.run(NamedRunnable.java:33)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
我认为它仍然试图连接到我的机器服务器。我尝试通过以下方式关闭开发环境：
"http://localhost:8081/index.android.bundle?platform=android?dev=false" -o "android/app/src/main/assets/index.android.bundle"
但我在服务器上收到此错误
Error: Unrecognized platform: android?dev=false
at DependencyGraph._getRequestPlatform (index.js:169:13)
at index.js:137:23
请说明我做错了什么。