Xamarin.iOS 绑定库/原生框架

Question

出于某种原因，我需要在我的 Xamarin.iOS 应用程序中使用 this 本机框架和问题来了，我不知道如何正确地进行绑定。

所以我理解正确，这个框架还使用了另一个 framework 我有点困惑，我到底需要做什么？

问题：

我是否需要实现静态库（这可能与 本地框架 相关吗）如 official documentation of Xamarin ?
我 make bindings for native framework 也可以使用另一个框架吗？或者我需要单独实现它们吗？
也许我应该将所有这些原生框架重新编写成 C# 版本？！？（但是这里出现了另一个问题，框架使用 ObjC 并且很难在 C# 对我来说)
实现我的目标的最佳方法是什么？（可能没有描述，你可以告诉我更多）。

有什么建议吗？谢谢！

Answer 1

这个库是用纯 ObjC 编写的。 Swift写的例子只有一个。鉴于库代码比较少，建议大家重新写成C#

Answer 2

好的，我终于制作了一个 静态库，但是出了点问题，我无法在 Emulator 上使用它当前时刻。 :(

我将逐步解释我是如何制作静态库的：

我从这个 repository 获得了所有源文件。
在XcodeIDE我做了静态库项目 之后我将所有源文件从存储库复制到我的项目。
通过 Carthage 我已经下载 this framework（正如我所解释的，源文件使用这个框架）并且我还在构建阶段 -> 复制文件（我选择框架的地方）到我的静态库。并成功构建（在部署目标 10.2）

.
接下来制作了MakeFile，成功生成了4个 Fat Binary .a 库没有任何问题。

Xcrun 命令显示：

 xcrun -sdk iphoneos lipo -info libOSMapKitAdapter.a
 Architectures in the fat file: libOSMapKitAdapter.a are: i386 armv7 x86_64 arm64

然后我在 Xamarin 中创建了 Binding Library 项目并添加了 Fat Binary Static Library as Native Reference（我将在下面显示我的 .csproj 文件）以及我已经为链接在 Static Library 内部的框架（我已经复制到项目路径）放置了相同的内容（也许它是多余的？）

此外，我还制作了名为 OSTransformation.framework.linkwith.cs 的附加文件，代码为：

通过Objective Sharpie我已经生成了ApiDefinition.cs 和 Structs.cs。命令：

sharpie bind --output=OSMapKitAdapter --namespace=OSMapKitAdapter --sdk=iphoneos10.2 /MyPath/OSMapKitAdapter/OSMapKitAdapter/*.h

结果是：

Parsing 5 header files...

Binding...
  [write] ApiDefinitions.cs
  [write] StructsAndEnums.cs

Binding Analysis:
  Automated binding is complete, but there are a few APIs which have been flagged with [
  Verify] attributes. While the entire binding should be audited for best API design
  practices, look more closely at APIs with the following Verify attribute hints:

  ConstantsInterfaceAssociation (1 instance):
    There's no foolproof way to determine with which Objective-C interface an extern
    variable declaration may be associated. Instances of these are bound as [Field]
    properties in a partial interface into a nearby concrete interface to produce a more
    intuitive API, possibly eliminating the 'Constants' interface altogether.

  PlatformInvoke (4 instances):
    In general P/Invoke bindings are not as correct or complete as Objective-C bindings (
    at least currently). You may need to fix up the library name (it defaults to '__
    Internal') and return/parameter types manually to conform to C calling conventionsfor
    the target platform. You may find you don't even want to expose the C API in your
    binding, but if you do, you'll probably also want to relocate the definition to a
    more appropriate class and expose a stronger type-safe wrapper. For P/Invoke guidance,
     see http://www.mono-project.com/docs/advanced/pinvoke/.

  Once you have verified a Verify attribute, you should remove it from the binding source
  code. The presence of Verify attributes intentionally cause build failures.

  For more information about the Verify attribute hints above, consult the Objective
  Sharpie documentation by running 'sharpie docs' or visiting the following URL:

    http://xmn.io/sharpie-docs

Submitting usage data to Xamarin...
  Submitted - thank you for helping to improve Objective Sharpie!

Done.

ApiDefinition.cs 的生成代码如下所示：

[Static]
    [Verify (ConstantsInterfaceAssociation)]
    partial interface Constants
    {
        // extern double OSMapKitAdapterVersionNumber;
        [Field ("OSMapKitAdapterVersionNumber", "__Internal")]
        double OSMapKitAdapterVersionNumber { get; }

        // extern const unsigned char [] OSMapKitAdapterVersionString;
        [Field ("OSMapKitAdapterVersionString", "__Internal")]
        byte[] OSMapKitAdapterVersionString { get; }
    }

    // @interface OSTileOverlay : MKTileOverlay
    [BaseType (typeof(MKTileOverlay))]
    interface OSTileOverlay
    {
        // @property (assign, nonatomic) BOOL clipOverlay;
        [Export ("clipOverlay")]
        bool ClipOverlay { get; set; }

        // -(instancetype _Nonnull)initWithAPIKey:(NSString * _Nonnull)apiKey product:(OSMapProduct)product __attribute__((objc_designated_initializer));
        [Export ("initWithAPIKey:product:")]
        [DesignatedInitializer]
        IntPtr Constructor (string apiKey, OSMapProduct product);
    }

    // @interface OSMapViewRegionRestriction : NSObject
    [BaseType (typeof(NSObject))]
    interface OSMapViewRegionRestriction
    {
        // @property (readonly, nonatomic) MKCoordinateRegion initialRegion;
        [Export ("initialRegion")]
        MKCoordinateRegion InitialRegion { get; }

        // -(void)updateMapViewRegionIfRequired:(MKMapView * _Nonnull)mapView;
        [Export ("updateMapViewRegionIfRequired:")]
        void UpdateMapViewRegionIfRequired (MKMapView mapView);
    }

    // @interface OSMapKitAdapter : NSObject
    [BaseType (typeof(NSObject))]
    interface OSMapKitAdapter
    {
    }

Structs.cs :

[Native]
public enum OSMapProduct : nint
{
    Road,
    Outdoor,
    Light,
    Night
}

static class CFunctions
{
    // extern NSString * NSStringFromOSMapProduct (OSMapProduct product);
    [DllImport ("__Internal")]
    [Verify (PlatformInvoke)]
    static extern NSString NSStringFromOSMapProduct (OSMapProduct product);

    // extern CLLocationCoordinate2D OSUpperLeftCorner ();
    [DllImport ("__Internal")]
    [Verify (PlatformInvoke)]
    static extern CLLocationCoordinate2D OSUpperLeftCorner ();

    // extern CLLocationCoordinate2D OSLowerRightCorner ();
    [DllImport ("__Internal")]
    [Verify (PlatformInvoke)]
    static extern CLLocationCoordinate2D OSLowerRightCorner ();

    // extern MKMapRect OSMapRectForUK ();
    [DllImport ("__Internal")]
    [Verify (PlatformInvoke)]
    static extern MKMapRect OSMapRectForUK ();
}

好的，现在我遇到了编译错误，因为它 shows on official tutorial of Xamarin bindings ，我需要用 [Verify] 检查 Fields属性并在解决问题后需要删除此 Attribute ，还添加 Protocol 属性等

ApiDefinition.cs的新版本：

   [Static]
    //[Verify(ConstantsInterfaceAssociation)]
    partial interface Constants
    {
        // extern double OSMapKitAdapterVersionNumber;
        [Field("OSMapKitAdapterVersionNumber", "__Internal")]
        double OSMapKitAdapterVersionNumber { get; }

        // extern const unsigned char [] OSMapKitAdapterVersionString;
        [Field("OSMapKitAdapterVersionString", "__Internal")]
        IntPtr OSMapKitAdapterVersionString { get; }
    }

    // @interface OSTileOverlay : MKTileOverlay
    [BaseType(typeof(MKTileOverlay))]
    [Protocol]
    interface OSTileOverlay
    {
        // @property (assign, nonatomic) BOOL clipOverlay;
        [Export("clipOverlay")]
        bool ClipOverlay { get; set; }

        // -(instancetype _Nonnull)initWithAPIKey:(NSString * _Nonnull)apiKey product:(OSMapProduct)product __attribute__((objc_designated_initializer));
        [Export("initWithAPIKey:product:")]
        [DesignatedInitializer]
        IntPtr Constructor(string apiKey, OSMapProduct product);
    }

    // @interface OSMapViewRegionRestriction : NSObject
    [BaseType(typeof(NSObject))]
    [Protocol]
    interface OSMapViewRegionRestriction
    {
        // @property (readonly, nonatomic) MKCoordinateRegion initialRegion;
        [Export("initialRegion")]
        MKCoordinateRegion InitialRegion { get; }

        // -(void)updateMapViewRegionIfRequired:(MKMapView * _Nonnull)mapView;
        [Export("updateMapViewRegionIfRequired:")]
        void UpdateMapViewRegionIfRequired(MKMapView mapView);
    }

    // @interface OSMapKitAdapter : NSObject
    [BaseType(typeof(NSObject))]
    [Protocol]
    interface OSMapKitAdapter
    {
    }

Structs 的新版本：

#if __UNIFIED__
[Native]
public enum OSMapProduct : long
{
    Road,
    Outdoor,
    Light,
    Night
}
#endif 
static class CFunctions
{
    // extern NSString * NSStringFromOSMapProduct (OSMapProduct product);
    [DllImport ("__Internal")]
    //[Verify (PlatformInvoke)]
    static extern NSString NSStringFromOSMapProduct (OSMapProduct product);

    // extern CLLocationCoordinate2D OSUpperLeftCorner ();
    [DllImport ("__Internal")]
    //[Verify (PlatformInvoke)]
    static extern CLLocationCoordinate2D OSUpperLeftCorner ();

    // extern CLLocationCoordinate2D OSLowerRightCorner ();
    [DllImport ("__Internal")]
    //[Verify (PlatformInvoke)]
    static extern CLLocationCoordinate2D OSLowerRightCorner ();

    // extern MKMapRect OSMapRectForUK ();
    [DllImport ("__Internal")]
    //[Verify (PlatformInvoke)]
    static extern MKMapRect OSMapRectForUK ();
}

问题是我遇到了这个错误：

Error MT5214: Native linking failed, undefined symbol: _OSMapKitAdapterVersionNumber. This symbol was referenced by the managed member OSTest.Constants.OSMapKitAdapterVersionNumber. Please verify that all the necessary frameworks have been referenced and native libraries linked. (MT5214)

Error MT5214: Native linking failed, undefined symbol: _OSMapKitAdapterVersionString. This symbol was referenced by the managed member OSTest.Constants.OSMapKitAdapterVersionString. Please verify that all the necessary frameworks have been referenced and native libraries linked. (MT5214)

Error MT5202: Native linking failed. Please review the build log. (MT5202)

我的 .csproj 文件 _ Xamarin.Bindings_ 项目看起来如何：

 <ItemGroup>
    <Reference Include="System" />
    <Reference Include="Xamarin.iOS" />
  </ItemGroup>
  <ItemGroup>
    <Compile Include="Properties\AssemblyInfo.cs" />
    <Compile Include="OSTransformation.framework.linkwith.cs" />
  </ItemGroup>
  <ItemGroup>
    <ObjcBindingApiDefinition Include="ApiDefinition.cs" />
  </ItemGroup>
  <ItemGroup>
    <ObjcBindingCoreSource Include="Structs.cs" />
  </ItemGroup>
  <ItemGroup>
    <NativeReference Include="OSTransformation.framework">
      <IsCxx>False</IsCxx>
      <Kind>Framework</Kind>
 </NativeReference>
      <NativeReference Include="..\..\..\MyPath\OSMapKitAdapter\libOSMapKitAdapter.a">
        <Kind>Static</Kind>
        <SmartLink>False</SmartLink>
      </NativeReference>
  </ItemGroup>
  <Import Project="$(MSBuildExtensionsPath)\Xamarin\iOS\Xamarin.iOS.ObjCBinding.CSharp.targets" />
</Project>

在真实设备上工作，但在模拟器上仍然会出现这个奇怪的错误。

更新：

只需确保您在链接器上选择了 "Link framework SDK only" 并且正常工作！

Xamarin.iOS 绑定库/原生框架

Xamarin.iOS Binding Libraries / Native Frameworks

static-libraries

xamarin.ios

ios

ios-frameworks

xamarin.ios-binding

问题：

更新：