Mobile

31-Aug-20 8:52

I'm trying to learn to call an Asp.Net Web API from a Xamarin Forms app. I'm testing my app using my phone plugged into my Dev PC running from VS 2019.

Here's my code so far:

private void Button_Clicked(object sender, EventArgs e)
{
    CustomerEntity customer = Test(1).Result;
}
public async Task<CustomerEntity> Test(int id)
{
    var url = "https:"  + "//localhost:44302/api/Customer/Get?Id=1";
    using (var client = new HttpClient())
    {
        client.BaseAddress = new Uri(url);
        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

        var response = await client.GetAsync(url); // Nothing happens after this!!

        CustomerEntity cust = JsonConvert.DeserializeObject<CustomerEntity>(await response.Content.ReadAsStringAsync());

        return cust;
    }
}

I can paste the URI into a browser and get results. When I click the button on my app that calls the above, I get no response after the GetAsync.

Anyone have any idea what's going on or how to debug this?

Thanks

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Afzaal Ahmad Zeeshan31-Aug-20 17:33

Afzaal Ahmad Zeeshan

31-Aug-20 17:33

Quote:
var url = "https:" + "//localhost:44302/api/Customer/Get?Id=1";

Unless your Android (or the mobile device) has a local server running on the machine that can respond to a localhost:44302 request, you will not receive a response and request will likely timeout and fail.

There are several ways to connect to a localhost based website:

You have a physical Android device that you are using for testing
You are using a virtualized device for testing

If you have a physical device, then try to send the request to the host (your development machine)'s IP address with the port number; for example, change localhost:44302 to 192.168.1.17:44302 (assuming your machine's address on the same network is 192.168.1.17)

If you are using the virtualized then this gets complicated and depends on several factors; what network setting is being used, which OS you are using, does the virtualization software support host-connections, etc. etc.

Oh, and the best of these is to use an online proxy that can tunnel your Android device with the local machine; something like NgRok can help here.

ngrok - secure introspectable tunnels to localhost

The sh*t I complain about
It's like there ain't a cloud in the sky and it's raining out - Eminem
~! Firewall !~

Kevin Marois1-Sep-20 6:12

1-Sep-20 6:12

I'm using my phone plugged into my PC.

When I paste this into the browser I get data back:

"https://localhost:44302/api/Customer/Get?Id=1"

When I paste this into the browser

"https://192.168.1.149:44302/api/Customer/Get?Id=1"

I get

Bad Request - Invalid Hostname

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Afzaal Ahmad Zeeshan1-Sep-20 8:50

Afzaal Ahmad Zeeshan

1-Sep-20 8:50

Quote:
I'm using my phone plugged into my PC.

I don't think that unless you also share the network via USB interface, you can access the PC's localhost.

Quote:
When I paste this into the browser I get data back:
"https://localhost:44302/api/Customer/Get?Id=1"

Because your "PC browser" has a process that is internally listening on the localhost (127.0.0.1) @ 44302. So it works.

Quote:
When I paste this into the browser
"https://192.168.1.149:44302/api/Customer/Get?Id=1"

This would "only" work if you have a machine or a process that is listening on 192.168.1.149 @ 44302. This is more likely a networking issue rather than an Android/PC problem. And, when you are on the same machine, you should always use 127.0.0.1 (aka localhost) instead of the machine's own private IP address.

Oh, one more tip, try only http:// and not the https://, or you will end up running in the SSL errors and you might assume the machine is down.

The sh*t I complain about
It's like there ain't a cloud in the sky and it's raining out - Eminem
~! Firewall !~

Kevin Marois1-Sep-20 11:13

1-Sep-20 11:13

This is all confusing to me. All I want to do is write a simple test Xamarin Forms app that connects to a Web API. I'm testing on my phone which is connected via USB to my PC.

WHat's the right way to do this? Can you point me to any resources for consuming a web API from Xamarin Forms?

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Mycroft Holmes1-Sep-20 12:20

Mycroft Holmes

1-Sep-20 12:20

I think if you use the emulator in vs2019 you may be able to access localhost (a guess). The issue is that the phone is a separate device without the infrastructure to access you PCs IIS server.

Never underestimate the power of human stupidity -
RAH
I'm old. I know stuff - JSOP

Angelina Brown28-Sep-20 21:31

Angelina Brown

28-Sep-20 21:31

I also face the same issue. Looking forward to get the right one.

OS crration

Morgan Atechi18-May-20 4:09

Morgan Atechi

18-May-20 4:09

How do I create an operating system using C programming language, and install it on my smartphone

Re: OS crration

Richard MacCutchan18-May-20 4:12

Publishing A Xamarin Forms App

18-May-20 4:12

You would need to write device drivers, boot sequence, kernel, support libraries etc. It will probably take a while.

Re: OS crration

ZurdoDev18-May-20 4:50

ZurdoDev

18-May-20 4:50

It's up to you. Where are you stuck?

Social Media - A platform that makes it easier for the crazies to find each other.

Everyone is born right handed. Only the strongest overcome it.
Fight for left-handed rights and hand equality.

Kevin Marois17-Apr-20 11:03

How to install Visual Studio Android Emulator in Windows 10 Home

17-Apr-20 11:03

I'm going to be bulding a Xamarin Forms app for a client in the construction industry. I can publish directly to my tablet via Visual Studio. But what options are there for gettting the app and updates to my client's tablets?

This isn't going to be a commercially available app that anyone can download from the app store. It's only for use on my client's tablets.

Thanks

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Paramu197316-Apr-20 16:41

Paramu1973

16-Apr-20 16:41

Hi,
Iam using VS2015, Windows-10 Home. When I try to install Visual Studio Android Emulator in Windows 10 Home, It asked me to install Hyper-V. Then I installed. But now Iam getting the error message

Visual Studio Android Emulator can not install in Windows 10 Home

Thanks

Re: How to install Visual Studio Android Emulator in Windows 10 Home

Richard MacCutchan16-Apr-20 21:45

Re: How to install Visual Studio Android Emulator in Windows 10 Home

16-Apr-20 21:45

The message is clear, the Android emulator cannot be run on that version of Windows.

Paramu197317-Apr-20 1:49

Paramu1973

17-Apr-20 1:49

Thank Richard.

Re: How to install Visual Studio Android Emulator in Windows 10 Home

Angelina Brown28-Sep-20 22:06

Angelina Brown

28-Sep-20 22:06

I do have the same query

How to install Visual Studio Android Emulator in Windows 10 Home

Paramu197316-Apr-20 19:43

Paramu1973

16-Apr-20 19:43

Hi,
I am using VS2015, Windows-10 Home. When I try to install, Visual Studio Android Emulator, it asked me to install Hyper-V, and then I installed. But now Iam receiving the message like Visual Studio Android Emulator can not installed in Windows 10 Home. Is there any solution.

Thanks

a pdf book mobile app

Member 1472128719-Jan-20 23:32

Member 14721287

19-Jan-20 23:32

Hi,

I am totally new to mobile app development, i am looking to develop a mobile app (hybrid) where a user can flip through a book (pdf) pages and place book marks where required.

I need some guidance as to which tech stack / framework to use. Any pointers will be of great help. If there is any similar app or sample project that will be awesome.

Regards,
SA

Richard MacCutchan20-Jan-20 0:36

20-Jan-20 0:36

Member 14721287 wrote:
I am totally new to mobile app development

In that case you first need to decide which language to use. If you already know Java then go for Android Studio, if C# then you may like to try Xamarin Forms. If you are not experienced in either of these languages then you have a long way to go before you can even start to think about how to build this application. There are lots of articles at Mobile Development[^] which can help.

Member 1472128720-Jan-20 0:38

Member 14721287

20-Jan-20 0:38

Thanks Richard,

I am quite comfortable with C#, i was wondering if i can do something with ionic or any other mobile dev framework.

Regards,
SA

Richard MacCutchan20-Jan-20 0:53

20-Jan-20 0:53

As far as I am aware, not used it myself, Xamarin Forms works well with C# for cross-platform development: see Xamarin.Forms documentation - Xamarin | Microsoft Docs[^].

Member 1472128720-Jan-20 0:57

Member 14721287

20-Jan-20 0:57

Sure ill check xamarin and also wait if someone else might have some other suggestions.

Thanks once again.

Regards,
SA