I downloaded VS2019 and proceeded to create a Solution and Project to learn Xamarin. I have tried using different templates (Mobile apps or just iOS) with the same result. Without changing anything in the resultant forms etc., if I build the solution I get the error that Forms does not exist in Xamarin. I have tried to download Xamarin.Forms, but it says it is already installed. I have searched and Googled and while there are similar questions of "name XXX does not exist in namespace YYY", none of those solutions apply in my case. I have tried to re-install VS, done a "repair" to VS. Many sites suggest closing and re-opening the solution (or cleaning), or restoring Nuget - none of that helps. The iOS project contains a reference to Xamarin.ios and I can see Xamarin.Forms under that so it does exist, but the project can't seem to find it. I know people like to see code here, but I haven't done any coding yet.
Solution image
Error image
AppDelegate
The solution was to manually add a folder called Thinktecture in C:/Program Files (x86)/Microsoft SDKs, then do an update of Xamarin.ios. It then gives a host of warnings about "Can't resolve the conflict between....", but it chooses the latest version and the Build works.
Related
I am using this nuget package
https://github.com/jamesmontemagno/MediaPlugin
It is available for both ios and android in pcl.
I am using it to make videos in my app.
Unfortunately, it has issues on iOS that are inside the project, not inside my code.
I am therefore trying to debug the project, not just implement the nuget library.
It does work fine on Android, so all I want to change is the iOS part.
Unfortunately, I dont know how to insert the same library when it isnt a nuget package but just the solution and also how to then adress it from pcl code.
I havent found a solution on google, but probably I dont know how to describe the problem well enought.
How can I debug an open source nuget package?
Thank you
Download or clone the src code,
Go to your project in VS,
Right click on your solution, choose Add -> Existing project,
Navigate to MediaPlugin-master\src\Media.Plugin and choose Media.Plugin.csproj file,
Right click on your iOS project (or whatever project where you use the plugin), choose Add -> Reference,
Check Media.Plugin and click OK,
Now you should be able to use the plugin in your project code after adding using Plugin.Media; (and the code of the plugin will be available to you).
I've got a cross platform (iOS and Android) Xamarin solution using .NET Standard 2.0. The solution is being built by Visual Studio 2017 (I've tried both the current and preview versions). The Forms and Android projects build fine. However, the iOS fails to build, with the following error:
1>CSC : error CS1703: Multiple assemblies with equivalent identity have been imported: 'C:\Users\newuser.nuget\packages\system.reflection.emit\4.3.0\ref\netstandard1.1\System.Reflection.Emit.dll' and 'C:\Program Files (x86)\Microsoft Visual Studio\Preview\Enterprise\Common7\IDE\ReferenceAssemblies\Microsoft\Framework\Xamarin.iOS\v1.0\Facades\System.Reflection.Emit.dll'. Remove one of the duplicate references.
I've tried many work arounds as described here:
oren.codes
www.hanselman.com
github.com/NuGet
Unfortunately none of these suggestions work. I have also tried to add the System.Reflection.Emit nuget package directly to the Forms and/or to the iOS projects directly. This doesn't work either. Note that originally, the The System.Reflection.Emit package wasn't referenced directly by anything in the solution. It is being pulled in by the following nuget packages which are being explicitly referenced:
Acr.DeviceInfo (5.0.5)
akavache (6.0.0-alpha0038)
AutoMapper (6.2.2)
Microsoft.Identity.Client (1.1.1-preview0040)
Newtonsoft.Json (10.0.3)
Finally, I have tried the update-package -reinstall command in the package console to reinstall all packages for the iOS project. This doesn't work either.
-- update
Just to make this clear, neither the Xamarin Forms or the Xamarin iOS project directly reference System.Reflection.Emit. That package is being pulled in as a dependency of other nuget packages, just from packages that are installed into the Xamarin Forms project. I have confirmed all of the dependencies that are referenced by Nuget, are using the same version. See these screenshots:
It seems to me that the problem (as the error says) is that there is an old version of System.Reflection.Emit that was installed by Visual Studio. However, I can't find a way of ignoring it and using the version of System.Reflection.Emit instead. As I've said above, I have tried to use a project.json file in the Xamarin.iOS project, and manually ignoring, but this doesn't work.
Does anyone else have any ideas?
As an aside, I notice that this bug is still open for Xamarin.
Xamarin Bugs
Managed to get this resolved thanks to an answer by #DirkWilhem on Xamarin Forums site.
Basically, add this to your Xamarin iOS project's .csproj file, with the other PackageReference nodes:
<PackageReference Include="System.Reflection.Emit">
<Version>4.3.0</Version>
<ExcludeAssets>all</ExcludeAssets>
</PackageReference>
Of course you need to make sure the nuget package has been added to the iOS package first.
Xamarin Forums discussion
After spending hours trying to resolve this myself I may have found a solution. Although it does feel wrong, it has got me past the issue.
Moving/Deleting the Xamarin.iOS version of System.Reflection.Emit.dll has solved the build problem for me and enabled me to deploy and run my app on a device. I don’t know what side effects it might have so will need more testing but I thought I’d share what’s worked for me so you can test it as well.
I was running on macOS Visual Studio 2017 but switched over to Windows to try and fix and first fixed on there then tried same approach on macOS and it worked as well.
On windows, go into the following directory and move the System.Reflection.Emit.dll somewhere else (you could just straight up delete it but I wanted to keep a copy I case this has some undesired effects down the track):
C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\ReferenceAssemblies\Microsoft\Framework\Xamarin.iOS\v1.0\Facades
On mac the following directory has it:
/Library/Frameworks/Xamarin.iOS.framework/Versions/Current/lib/mono/Xamarin.iOS/Facades
Like I say, it feels wrong but for now it’s got me past an issue that’s had me blocked for a couple of days so willing to just move on and hope there’s no side effects. I’d be interested to know your experience with it and if you come across anything else for the future too.
I’ll post this same comment on the Xamarin forums post (https://forums.xamarin.com/discussion/120814/xamarin-ios-project-cs1703-multiple-assemblies-with-equivalent-identity-have-been-imported) as well for future reference.
I had the same issue around a custom Nuget packages that we created and consumed in a separate project. We got around this issue by removing the automatic Nuget building checkbox in the "options" for the project. This does add the extra step of "Create Nuget Package" but one we pushed it to our Nuget repo and consumed it in our project, the errors vanished.
The problem showed up when we updated the sub-projects from PCLs to .netstandards (2.0).
I need to implement Map functionality into an application that I'm building.
And I was folliwing this guide.
I downloaded the package and did all of the configuration.
I haven't implemented the Map class into my project yet, I only did the configuration required for both platforms (Android and iOS).
The Portable project and the iOS project are fine, the problem here is the Android project.
It has some broken references, these ones:
And when I try to compile the Android project, I get this error and these warnings:
Can anybody give me a hand? Thanks in advance.
EDIT:
As a sidenote, I'm using the Sdk installed by Android Studio, and that one has the latest Google Play Services installed.
UPDATE:
I just upgraded the version of my Xamarin.GooglePlayServices one by one (the one listed up there in the first image) for some reason it downloaded a really old version of those. So I just upgraded them, and it seems those references are fine now.
But I still get the error:
The "ResolveLibraryProjectImports" tasks failed unexpectedly.
SOLUTION:
I unloaded the Android project, added this:
<UseShortFileNames>True</UseShortFileNames>
To every property group in the .csproj file.
Load my android project back, and it all worked fine now.
I follow this guide trying to create a SQLite database to my proyect. But always got same error, doing the exactly steps of the article.
System.Exception: This is the 'bait'. You probably need to add one of the SQLitePCLRaw.bundle_* nuget packages to your platform project.
Have you added the SQLite package to all your projects? You need to add it to the app projects as well as the PCLs.
This is what the error is telling you. It uses a trick called 'bait and switch' whereby it installs a dummy assembly in the PCL with a particular interface, and in the Android and iOS apps it installs a platform specific assembly with an identical interface that actually does the interactions with the database. The idea is you code against the PCL, but at run time the platform specific version of the library is used. You can read more about this pattern at https://web.archive.org/web/20161209075521/http://log.paulbetts.org/the-bait-and-switch-pcl-trick/
Essentially though, this error is telling you that you haven't installed the NuGet package in your platform-specific projects.
I was experiencing this issue despite following the instructions in the error message and installing the missing library.
A clean & rebuild solved it
I had installed the packages (SQLite-net PCL) but I uninstalled them, then reinstalled. And then I cleaned the solution and rebuilded it and now it works.
I have downloaded the Xamarin.Forms solution from GitHub and I am trying to build the solution. Visual Studio does not build, generating more than 70 errors, as simple as the one below:
"The type or namespace name 'IOnClickListener' could not be found (are
you missing a using directive or an assembly reference?"in
Xamarin.Forms.Platform.Android\AppCompat\ButtonRenderer.cs
When I investigate the code, I see that there is really no reference to Android.Views.View in the using statements, so it seems fair.
Am I making a mistake somewhere?
It's not easy to get to the answer without digging into the logs but here are some steps that have helped me in the past.
Android Specific Steps:
Check the logs for any problems that stand out, look at the top most error first and work your way down. Output window -> Show output from Xamarin Diagnostic
If you find unzipping problems you might have to visit the Xamarin folders to delete the zip causing problems and Xamarin will download a new one.
C:\Users{USER}\AppData\Local\Xamarin
If you get loads of Xaml and Resource errors you might have to delete the contents of the file.
Resources\Resource.Designer.cs
After deleting the content(not the file), clean the solution, rebuild the project.
If you still have problems try to either downgrade Xamarin.Forms or upgrade it.
Change Api level to a higher one on the project properties.
Hope one of these helps.