I have created a Xamarin.Forms solution and I want to add another layer to access the API. So I added another PCL Project to the same solution and tried to add a reference to this new project from the PCL Project that comes by default in Xamarin.Forms. But it does not allow me to add a reference and gives me this error. Can you tell me why this is happening, how to get over it or how to add a PCL reference correctly?
You probably want to read up on what a PCL exactly is.
In short: a PCL has a specific profile, which is specified by the platforms you are targeting. If you go into the properties of your PCL project, you can check each platform that you want to target. With each extra target that you check, the profile changes. The profile defines what subset of the .NET framework is available to you.
For instance, the other day there was a question about the String.Copy method. If this method is supported by .NET framework 4.5, but not Xamarin.iOS and you target these two, the method is not available to you. Only the parts of the .NET framework are available that are in the intersection of all platforms that you target. So each target that you target should support the methods that you can use.
That being said; this is also the reason why referencing another PCL should have the same platforms targeted.
Related
So yesterday this line:
ATTrackingManager.RequestTrackingAuthorization((status) => {
if (status == ATTrackingManagerAuthorizationStatus.Authorized)
{
}
was working code (in my cross-platform Xamarin.Forms PCL).
Today xamarin.ios received an update.
In the PCL project, the tracking manager is not found anymore. Intellisense doesnt know what it is anymore and I cannot debug the app.
It is recognized in the xamarin.ios project, but I need to access it from my PCL.
Anyone having the same issue and / or has already found a solution?
How can I rollback to xamarin.ios before the one I received today?
Don't need to rollback. As a test, I updated
Visual Studio (which also updated Xamarin.iOS).
XCode to 14.5.1.
Then I added a line of code to an existing Xamarin Forms solution, that referenced AppTrackingTransparency.ATTrackingManager. This was recognized as valid code. I Also tried just ATTrackingManager, and Intellisense correctly told me I needed using AppTrackingTransparency.
So its there now.
That namespace+classname is specific to iOS, so must be referenced from the iOS-specific project. (If it previously was referenceable in the PCL, that was probably a bug that has since been corrected; such code would break on any other platform.)
First step:
In your iOS project, write code that references that class.
Second step:
You need to know how to use your custom iOS code from the cross-platform Xamarin Forms PCL.
I won't repeat that here - there are multiple Q&As on that topic.
google "stackoverflow xamarin forms call platform specific code".
I am using Visual Studio For Mac. My Xamarin Forms project is quite large and contains many content pages. Some of them will be only used in android project and some of them only used in iOS project. There is no problem when I compile the project into android. However, when I want to compile the project into iOS, it seems like did not accept anything related to android. Please refer to the screenshot. There is no way I can include the android specialised reference and compile into iOS project. So, any idea to deal with this? Maybe there is a way to force build the iOS project no matter what? The error from the screenshot is from the page that will be only used in android. So what I can do for now is delete the page when I want to compile as iOS and recreate the page when I want to used it for android. But there are plenty of them, it is too heavy for me to do this every time. Please help.
You can't call platform specific APIs at the .NET standard libraries that are used to host Xamarin.Forms code by default.
Basically you have those options:
1) using shared project instead of library and using conditional compiling (easier but it is now not available as the option when creating the project)
2) using dependency injection.
I've got a WPF App using the latest version of Prism for WPF (6.3.0) and Unity. Just a few modules. It works great.
When I manage NuGet packages for my solution, it tells me that there is a new version of Unity (5.4.0) available. Unfortunately, if I try to update to that version, I can no longer build.
It's pretty clear to see why: Upgrading unity via this method removes all references to it (Unity) from my project. Specifically the following 3 references completely disappear from all my projects without any replacement:
Microsoft.Practices.Unity
Microsoft.Practices.Unity.Configuration
Microsoft.Practices.Unity.RegistrationByConvention
(The Prism references remain, of course)
Error messages tell me that IUnityContainer is defined in an unreferenced assembly (Microsoft.Practices.Unity. 4.0.0.0). Given that it removed those assemblies, this all makes sense.
If I then try to go looking to add Unity back in, the Add Project Reference dialog cannot even find Microsoft.Practices.Unity when I search for it.
Now this isn't that big of a deal. I didn't need to upgrade. and it's easy for me to revert back. But I want to understand why this is failing for future reference.
Does this mean that Prism is tied to the older version of Unity and I just shouldn't upgrade?
Does this mean that types have moved to different namespaces and I need to make some other fix?
Some other reason?
Among the Unity 5 updates included a change of namespaces which as you noticed was a major breaking change. There are no plans for Prism 6 to support Unity 5, however the current Prism 7 previews (which is available for WPF) have updated both the Common Service Locator and Unity.
https://www.nuget.org/packages/Prism.Unity/7.0.0.336-pre
I am new xamarin.forms framework, When I started to work for cross platform application for making new solution (new solution->mobile apps), I got following three options for moving further:
Blank App(Xamarin.Forms Portable)
Blank App(Xamarin.Forms Shared)
Class Library(Xamarin.Forms Portable)
After investigating a lot, among those i did not create any difference. Can anyone tell me the difference with example.
Xamarin has the answer to your question here, but I'll give you a short rundown here as well.
Class Library(Xamarin.Forms Portable)
Is an Portable Class Library you can put classes in, which would then be usable by either an Android, iOS or WP app.
Blank App(Xamarin.Forms Portable)
Creates a set of apps for Android, iOS and possibly WP using a Portable Class Library for the common parts
Blank App(Xamarin.Forms Shared)
Creates a set of apps for Android, iOS and possibly WP using a Shared Library for the common parts
The difference between PCL and Shared is that a PCL library is compiled once, and then referenced as a library by each app. A Shared library is compiled directly into each app (and is thus compiled three times as opposed to one for the PCL)
I have a Flex Library Project which has both Flex specific classes, and Air specific classes.
When I reference the library in an Air project, the compiler complains about an overriding contextMenu in mx.containers.Panel, saying that the param should be of type NativeMenu (instead of ContextMenu). If I switch it over to NativeMenu then it compiles fine.
The issue is when I reference the library in a Flex Project. This time it complains that it doesn't know the type NativeMenu. If I try to change it back to ContextMenu, then I get the same error as above.
I've searched google to no avail (found that someone else encountered the exact same problem: http://forums.adobe.com/thread/598791?tstart=-1 )
The docs don't help too much either, except stating the above: http://livedocs.adobe.com/flex/3/langref/flash/display/InteractiveObject.html#contextMenu
I'm thinking that its just not possible to do the mixing of Flex vs Air SDKs that I want, but I was hoping that maybe someone has figured this out.
Thanks!
You can't really target the web Flash Player and the desktop Player using the same project.
I would recommend encapsulating out as much functionality as possible into a library project. Then create a single Flex project and a single AIR project, both using the same library project.
Each respective project can extend, or replace, the different functionality.
I am not sure if this is the exact same problem, but I was having an issue with being able to reference the AIR libraries in a Flex Library project and found the (rather simple) solution.
Using Flash Builder 4.5, when creating a Flex Library Project, (right-click .. New.. Flex Library Project) there is a checkbox for "Include Adobe Air Libraries" at the bottom. This must be checked or AIR libraries will not be included.
When you select the version of SDK/AIR you are using in the dropdown, the message should also indicate what the minimum version of AIR required is for your application.