我开始探索 Net.Maui 与 Blazor 和 gRPC Service 相结合的新版本，使用“Net Maui Blazor App Template”作为 Client 和“gRPC Service AspNetCore template”作为 Server。
因此，当我在“Windows 平台”下运行且没有任何错误时，应用程序也可以正常工作，但是当我在“Android 平台”下运行相同的应用程序时，对 gRPC 服务器的调用会出现以下错误：
Status(StatusCode="Internal", Detail="Error starting gRPC call. WebException: Failed to connect to localhost/127.0.0.1:7215 ConnectException: Failed to connect to localhost/127.0.0.1:7215", DebugException="System.Net.WebException: Failed to connect to localhost/127.0.0.1:7215
堆栈跟踪：
---> Java.Net.ConnectException: Failed to connect to localhost/127.0.0.1:7215
at Java.Interop.JniEnvironment.InstanceMethods.CallVoidMethod(JniObjectReference instance, JniMethodInfo method, JniArgumentValue* args) in /Users/builder/azdo/_work/2/s/xamarin-android/external/Java.Interop/src/Java.Interop/Java.Interop/JniEnvironment.g.cs:line 11643
at Java.Interop.JniPeerMembers.JniInstanceMethods.InvokeAbstractVoidMethod(String encodedMember, IJavaPeerable self, JniArgumentValue* parameters) in /Users/builder/azdo/_work/2/s/xamarin-android/external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniInstanceMethods_Invoke.cs:line 17
at Javax.Net.Ssl.HttpsURLConnectionInvoker.Connect() in /Users/builder/azdo/_work/2/s/xamarin-android/src/Mono.Android/obj/Release/net6.0/android-31/mcw/Javax.Net.Ssl.HttpsURLConnection.cs:line 535
at Xamarin.Android.Net.AndroidMessageHandler.<>c__DisplayClass122_0.<ConnectAsync>b__0() in /Users/builder/azdo/_work/2/s/xamarin-android/src/Mono.Android/Xamarin.Android.Net/AndroidMessageHandler.cs:line 398
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.<>c.<.cctor>b__271_0(Object obj)
at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location ---
at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
--- End of stack trace from previous location ---
at Xamarin.Android.Net.AndroidMessageHandler.DoProcessRequest(HttpRequestMessage request, URL javaUrl, HttpURLConnection httpConnection, CancellationToken cancellationToken, RequestRedirectionState redirectState) in /Users/builder/azdo/_work/2/s/xamarin-android/src/Mono.Android/Xamarin.Android.Net/AndroidMessageHandler.cs:line 447
--- End of managed Java.Net.ConnectException stack trace ---
java.net.ConnectException: Failed to connect to localhost/127.0.0.1:7215
at com.android.okhttp.internal.io.RealConnection.connectSocket(RealConnection.java:147)
at com.android.okhttp.internal.io.RealConnection.connect(RealConnection.java:116)
at com.android.okhttp.internal.http.StreamAllocation.findConnection(StreamAllocation.java:186)
at com.android.okhttp.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:128)
at com.android.okhttp.internal.http.StreamAllocation.newStream(StreamAllocation.java:97)
at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:289)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:232)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:465)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:131)
at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.connect(DelegatingHttpsURLConnection.java:90)
at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:30)
--- End of managed Java.Net.ConnectException stack trace ---
java.net.ConnectException: Failed to connect to localhost/127.0.0.1:7215
at com.android.okhttp.internal.io.RealConnection.connectSocket(RealConnection.java:147)
at com.android.okhttp.internal.io.RealConnection.connect(RealConnection.java:116)
at com.android.okhttp.internal.http.StreamAllocation.findConnection(StreamAllocation.java:186)
at com.android.okhttp.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:128)
at com.android.okhttp.internal.http.StreamAllocation.newStream(StreamAllocation.java:97)
at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:289)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:232)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:465)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:131)
at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.connect(DelegatingHttpsURLConnection.java:90)
at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:30)
--- End of inner exception stack trace ---
at Xamarin.Android.Net.AndroidMessageHandler.DoProcessRequest(HttpRequestMessage request, URL javaUrl, HttpURLConnection httpConnection, CancellationToken cancellationToken, RequestRedirectionState redirectState) in /Users/builder/azdo/_work/2/s/xamarin-android/src/Mono.Android/Xamarin.Android.Net/AndroidMessageHandler.cs:line 454
at Xamarin.Android.Net.AndroidMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) in /Users/builder/azdo/_work/2/s/xamarin-android/src/Mono.Android/Xamarin.Android.Net/AndroidMessageHandler.cs:line 329
at Grpc.Net.Client.Web.GrpcWebHandler.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken) in /_/src/Grpc.Net.Client.Web/GrpcWebHandler.cs:line 165
at Grpc.Net.Client.Internal.GrpcCall`2.<RunCall>d__72[[AppsShared.Protos.Credentials, AppsShared, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[AppsShared.Protos.LoginStatus, AppsShared, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].MoveNext() in /_/src/Grpc.Net.Client/Internal/GrpcCall.cs:line 469")
这里的设置：
gRPC 客户端频道：
builder.Services.AddSingleton(services =>
{
var httpHandler = new GrpcWebHandler(new GrpcWebHandler(GrpcWebMode.GrpcWeb, new HttpClientHandler()));
return GrpcChannel.ForAddress("https://localhost:7215", new GrpcChannelOptions { HttpHandler = httpHandler });
});
gRPC 客户端调用
var loginer = new Loginer.LoginerClient(channel);
var loginStatus = await loginer.LoginAsync(new Credentials { Password = password , UserName = userName });
安卓清单：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android">
<uses-sdk android:minSdkVersion="21" android:targetSdkVersion="31" />
<application android:allowBackup="true" android:icon="@mipmap/appicon" android:roundIcon="@mipmap/appicon_round" android:supportsRtl="true"></application>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
</manifest>
Android MainActivity.cs
using Android.App;
using Android.Content.PM;
using Android.OS;
using Android.Runtime;
using Microsoft.Maui;
using Microsoft.Maui.Essentials;
namespace MauiBlazorBase
{
[Activity(Theme = "@style/Maui.SplashTheme", MainLauncher = true,
ConfigurationChanges = ConfigChanges.ScreenSize |
ConfigChanges.Orientation | ConfigChanges.UiMode |
ConfigChanges.ScreenLayout | ConfigChanges.SmallestScreenSize)]
public class MainActivity : MauiAppCompatActivity
{
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
Platform.Init(this, savedInstanceState);
}
public override void OnRequestPermissionsResult(int requestCode, string[] permissions,
[GeneratedEnum] Permission[] grantResults)
{
Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults);
base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
}
}
}
预先感谢您的提示。
皮尔卡洛