Can not compile after migrating unified api in xamarin forms - xamarin

We have migrated the xamarin forms project to unified api.
But we have the strange compile error like this:
Could not AOT the assembly '.../iOS/obj/iPhone/Debug/mtouch-cache/Build/Xamarin.Forms.Labs.dll
So I changed the settings in iOS project's options.
In ios Build Tab of Project options(iOS) I changed the "don't link" to "Link all assemblies".
But the app is crashed when it is started.
xamarin version is 5.7.1(build 17).
xamarin forms's version is 1.3.5.6337.
xamarin forms labs's version is 1.0.1.5.
Please help me if you have the experience with this error.

Replace Xamarin.Forms.Labs with XLabs.Forms.
There has been a major refactoring on how the XLabs project is structured so your existing project based on the 1.x.x will break. The reason for the refactoring was simple; separate functionality that does not depend on Xamarin.Forms into different assemblies. This allows the use of functionality like IoC, Serialization and even platform specific services without referencing XF.
To upgrade:
Uninstall any existing Xamarin.Forms.Labs packages from your
project.
Install XLabs.Forms package to your projects (PCL, iOS, Droid & WP). This will update Xamarin.Forms to the latest stable release (1.4.x)
Refactor code to reference the correct namespaces.

Related

Cannot find "cross-platform using PCL" while creating a xamarin app

I want to create a xamarin cross platform using PCL. I do not find this option while creating a project. Am I missing any installations?
Is "Xamarin.UITest Cross Platform Test Project" similar to that? But that does not open Android and IOS directories in it
The PCL option is deprecated .
From the official documentation:
Portable Class Libraries (PCLs) are considered deprecated in the
latest versions of Visual Studio. While you can still open, edit, and
compile PCLs, for new projects it is recommended to use .NET Standard
libraries to access a larger API surface area.
If you wan't to create a Xamarin.Forms solution, you must select the Mobile App (Xamarin.Forms) template. Nowadays, everything moved to .netstandard 2.0

Using platform specific httclienthandler?

In xamarin should I always configure the app to use the platform specific httpclienthandler or is it ok to use the default httpclienthandler. I have read that you get better performance but I was just wondering if it is so much better that this should be a standard practice for all my xamarin apps.
It is ok to use httpclienthandler in the portable class library(pcl). Feel free to use HttpClient to run in a PCL library that supports iOS, Android, and WP8.
Here how i did it. Restart from a clean project.
Create a PCL with iOS, Android, .NET 4.5 and WP8. Add the microsoft Http nuget. It will install 2 other packages into the PCL.
Create the Android and iOS projects. Reference your PCL in both projects. For me that's all. It just works.
You may add the reference "System.Net.Http" in both platform projects. The reference is under Assemblies/Framework.
NEVER add Microsoft.Http nuget in any native project, nor the BCL nuget. It will create mess and you'll have to clean lots of things before it can work again.
It is extremely important that your NuGet manager is up to date, go to Tools-> Extensions and updates -> Updates

Multiple errors after updating Xamarin Forms

I'm using Visual Studio 2017, and I stared a new Xamarin Forms app:
Create New project - Cross Platform App (Xamarin)
Blank App, and I chose Portable Class Library (PCL)
The app compiles and runs.
Now I right click the solution and choose Manage Nuget packages for solution, and it tells me I'm running version 23.3.0 and I should update to 25.4.0.1
After the update and 3 VS reboots, it gives me a host of errors I have been trying to solve for an hour including googling.
All theme related.
I tried removing the styles.xml file all together. I removed the theme from the reference to the theme from the manafest and it keeps putting it back.
I can't figure out what I'm doing wrong. I have not written any code.
Xamarin Forms requires a specific version of the Android Support libraries. Do not update them.
Delete your project and create a new one.
It is possible to get round this limitation by ensuring you are using a specific version of Android and by updating all Android SDK's, but for a beginner I would recommend just using the support libraries that are installed alongside Xamarin Forms.

Xamarin Forms and Entity Framework Core NetStandard

Recently Xamarin announced support for NetStandard (see https://releases.xamarin.com/stable-release-cycle-7-service-release-1/) and the recently shipped Entity Framework Core supports NetStandard. There was a recent issue with the SQLite.Native package that has been resolved (see https://github.com/aspnet/EntityFramework/issues/4269) but when I build the Android version of a Xamarin Forms application it appears it does not include all the assemblies in the output that are needed by the Entity Framework and therefore the application will not run and crashes on the first line of EF code to retrieve data. The UWP version appears to work just fine so this seems like an issue with Android (possibly iOS too).
Has anyone run into this and know a way around it so that the compiled Xamarin Forms Android application will run using Entity Framework Core to access a SQLite database?
Thank you in advance.
Here are the steps you can follow.
Create a Xamarin.Forms project.
Convert the PCL project's properties to .NET Standard 1.3
Install Entity Framework Core and other EF Core stuffs
I have prepared a small hello world project at Github Here.
need to use -linkskip to inform compiler not to remove references.

MvvmCross as "Native" Libraries

I have a project which greatly depends on ServiceStack, unfortunately the V4 releases, which includes PCL release for most platforms(especially after forking out for a Xamarin Licence), is just way out of my price range as an ISV. I have cloned the MvvmCross code but before I start messing around I would like to know what pitfalls I could run into when attempting to create a Non PCL based version compatible with the platforms I target (Currently Xamarin.Android, WPF and WinRT). The idea would be to able to reuse the code for the WPF project to build Android and WinRT clients.
Does anyone have any pointers?
I don't think there is any problem or pitfall with what you are describing - and I don't think you'll need to fork the MvvmCross source.
You should be able to build your apps as native code, and should then be able to reference the MvvmCross PCL libraries directly from the native libraries you are building - you don't need to rebuild MvvmCross to do this. Plenty of people already use MvvmCross using "file linking" rather than PCLs - it's not the default setup encouraged by the Nuget packages, but it still works fine.

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