async/await method crash web services response in android but same code work successfully in other

ShahabuddinVansiwala

async/await method crash web services response in android but same code work successfully in window Phone and iOS apps in xamarin Native Appliation.

Xamarin Native Application (PCL)

I have created a Native application using portable Class libarary.

I request to REST API that gives the following response.

    {
    code: 200,
    status: "ok",
    message: "hello"
    }

my Portable class library code in xamarin.forms is

test.xaml.cs

    public class jsonResponseClass
    {
            public string code { get; set; }
            public string status { get; set; }
            public string message { get; set; }
    }
    public partial class test : ContentPage
    {
            public async void getDatas()
            {
                var cl = new HttpClient();
                var result = await cl.GetStringAsync("http://192.168.1.125/apps/jara/web/api/user/test");
                jsonResponseClass des = JsonConvert.DeserializeObject<jsonResponseClass>(result);
                lbl1.Text = des.code + " " + des.status + " " + des.message;
            }
            public test()
            {
                InitializeComponent();
                getDatas();
            }
    }

Main file in Portable class library (PCL)

App.cs

namespace NativeAppsWithWCF
{
    public class App : Application
    {
        public App()
        {
            MainPage = new test();
        }
        protected override void OnStart()
        {
            // Handle when your app starts
        }

        protected override void OnSleep()
        {
            // Handle when your app sleeps
        }

        protected override void OnResume()
        {
            // Handle when your app resumes
        }
    }
}

my visual studio solution explorer is

Using this above code I can successfully show output in iOS and Window Phone Apps.

But when i Run Android apps then crash the apps and not show output.

When i debug android program then cursor remove after this line.

var result = await
cl.GetStringAsync("http://192.168.1.125/apps/jara/web/api/user/test");

After this line i got an error and stop the execution of program.

See the screen after got error..

How to prevent this error ?

AdamP

@ShahabuddinVansiwala - check the output window or Android Device Logging (logcat) messages to see the issues on Android devices. I would probably have a guess that you might not have set the Internet permission in your Android app but without the errors I couldn't tell you.

https://developer.xamarin.com/guides/android/deployment,_testing,_and_metrics/android_debug_log/ - if you didn't know about the android logging.

ShahabuddinVansiwala

@Adamp Already i have given the permission of Internet.

the main problem is after below line .... the execution has stopped and exit the current method.

There are no give any exception or error message.

var result = await
cl.GetStringAsync("http://192.168.1.125/apps/jara/web/api/user/test");

This problem is only in android. I have successfully run iOS and Window phone project with same coding.

AdamP

@ShahabuddinVansiwala - please provide the logcat output so we can see what Android errors are occurring. That will give more information.

ShahabuddinVansiwala

@AdamP

Finally I have solved the problem after lots of R&D.

Problem in Network Connectivity.

I have solve this issue after setting of Network Connectivity in Android Emulator.

Follow Below step..

Open VS Android Emulator >> Go to Setting >> Turn ON WIFI >>

There are "Wired eth1" Network available.

Long Press on "Wired eth1" Network

Then Click on >> Modify Network >> Change "IP Setting" as "Static" >>

Change IP address of your Network.

After this setting I have Solved my Issue and Get a Response from REST API.

Thank you.

sqlt

@ShahabuddinVansiwala
Thanks so much for your reply. That was exactly my problem. Spent over an hour trying to solve that. The only thing I'd add is that I didn't have to change the IP address, just changing the IP Setting to static and saving with the default IP it provided worked for me.

AndreLuiz.1614

I'm having the same problem, however I'm running the app on the physical phone by the usb.

The error happens exactly in the httpClient.GetAsync () call;

Already i have given the permission of Internet.

Error:
Time Device Name Type PID Tag Message
03-28 08:14:37.907 Sony D6643 Error 28667 mono-rt [ERROR] FATAL UNHANDLED EXCEPTION: System.Net.Http.HttpRequestException: An error occurred while sending the request ---> System.Net.WebException: Error: SecureChannelFailure (The authentication or decryption has failed.) ---> System.IO.IOException: The authentication or decryption has failed. ---> System.IO.IOException: The authentication or decryption has failed. ---> Mono.Security.Protocol.Tls.TlsException: The authentication or decryption has failed.
at Mono.Security.Protocol.Tls.RecordProtocol.EndReceiveRecord (System.IAsyncResult asyncResult) [0x0003a] in /Users/builder/data/lanes/4009/3a62f1ea/source/mono/mcs/class/Mono.Security/Mono.Security.Protocol.Tls/RecordProtocol.cs:430
at Mono.Security.Protocol.Tls.SslClientStream.SafeEndReceiveRecord (System.IAsyncResult ar, System.Boolean ignoreEmpty) [0x00000] in /Users/builder/data/lanes/4009/3a62f1ea/source/mono/mcs/class/Mono.Security/Mono.Security.Protocol.Tls/SslClientStream.cs:256
at Mono.Security.Protocol.Tls.SslClientStream.NegotiateAsyncWorker (System.IAsyncResult result) [0x00071] in /Users/builder/data/lanes/4009/3a62f1ea/source/mono/mcs/class/Mono.Security/Mono.Security.Protocol.Tls/SslClientStream.cs:418
--- End of inner exception stack trace ---
at Mono.Security.Protocol.Tls.SslClientStream.EndNegotiateHandshake (System.IAsyncResult result) [0x00035] in /Users/builder/data/lanes/4009/3a62f1ea/source/mono/mcs/class/Mono.Security/Mono.Security.Protocol.Tls/SslClientStream.cs:396
at Mono.Security.Protocol.Tls.SslStreamBase.AsyncHandshakeCallback (System.IAsyncResult asyncResult) [0x0000c] in /Users/builder/data/lanes/4009/3a62f1ea/source/mono/mcs/class/Mono.Security/Mono.Security.Protocol.Tls/SslStreamBase.cs:101
--- End of inner exception stack trace ---
at Mono.Security.Protocol.Tls.SslStreamBase.EndRead (System.IAsyncResult asyncResult) [0x00051] in /Users/builder/data/lanes/4009/3a62f1ea/source/mono/mcs/class/Mono.Security/Mono.Security.Protocol.Tls/SslStreamBase.cs:883
at Mono.Net.Security.Private.LegacySslStream.EndAuthenticateAsClient (System.IAsyncResult asyncResult) [0x00011] in /Users/builder/data/lanes/4009/3a62f1ea/source/mono/mcs/class/System/Mono.Net.Security/LegacySslStream.cs:475
at Mono.Net.Security.Private.LegacySslStream.AuthenticateAsClient (System.String targetHost, System.Security.Cryptography.X509Certificates.X509CertificateCollection clientCertificates, System.Security.Authentication.SslProtocols enabledSslProtocols, System.Boolean checkCertificateRevocation) [0x00000] in /Users/builder/data/lanes/4009/3a62f1ea/source/mono/mcs/class/System/Mono.Net.Security/LegacySslStream.cs:445
at Mono.Net.Security.MonoTlsStream.CreateStream (System.Byte[] buffer) [0x0004e] in /Users/builder/data/lanes/4009/3a62f1ea/source/mono/mcs/class/System/Mono.Net.Security/MonoTlsStream.cs:105
--- End of inner exception stack trace ---
at System.Net.HttpWebRequest.EndGetResponse (System.IAsyncResult asyncResult) [0x0005e] in /Users/builder/data/lanes/4009/3a62f1ea/source/mono/mcs/class/System/System.Net/HttpWebRequest.cs:1029
at System.Threading.Tasks.TaskFactory1[TResult].FromAsyncCoreLogic (System.IAsyncResult iar, System.Func2[T,TResult] endFunction, System.Action1[T] endAction, System.Threading.Tasks.Task1[TResult] promise, System.Boolean requiresSynchronization) [0x00014] in /Users/builder/data/lanes/4009/3a62f1ea/source/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/FutureFactory.cs:550

Thanks.

AndreLuiz.1614

I put an exception and gave this error...

AndreLuiz.1614

I solved my problem too, if anyone needs to follow the solution:

This is quite an old post, but for people still getting this, know that the answer of EdHubbel is correct.

If you encounter this issue using the HttpClient class like this HttpClient client = new HttpClient();

then install the "modernhttpclient" nuget package to your project (both PCL, and native projects), and then change your HttpClient class initialization to this:

HttpClient client = new HttpClient(new NativeMessageHandler());

The NativeMessageHandler class will handle for you these certificates issues

reference: https://forums.xamarin.com/discussion/10405/the-authentication-or-decryption-has-failed-in-the-web-request

Thanks!

himel951

Lot of tnx AndreLuiz.1614. I just followed your instruction plus add the Internet Access in the android manifest. now HttpClient works without any error.