Unhandled Exception:
    System.NullReferenceException: Object reference not set to an instance of an object
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.Save (Xamarin.Android.Tools.ApiXmlAdjuster.JavaTypeParameters typeParameters, System.Xml.XmlWriter writer, System.String indent) [0x000f0] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.SaveCommon (Xamarin.Android.Tools.ApiXmlAdjuster.JavaMember m, System.Xml.XmlWriter writer, System.String elementName, System.String abs, System.String native, System.String ret, System.String sync, System.String transient, System.String type, System.String typeGeneric, System.String value, System.String volat, Xamarin.Android.Tools.ApiXmlAdjuster.JavaTypeParameters typeParameters, System.Collections.Generic.IEnumerable`1[T] parameters, System.Collections.Generic.IEnumerable`1[T] exceptions, System.Nullable`1[T] extBridge, System.String jniReturn, System.Nullable`1[T] extSynthetic) [0x001a2] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.Save (Xamarin.Android.Tools.ApiXmlAdjuster.JavaMethod method, System.Xml.XmlWriter writer) [0x0018c] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.SaveTypeCommon (Xamarin.Android.Tools.ApiXmlAdjuster.JavaType cls, System.Xml.XmlWriter writer, System.String elementName, System.String abs, System.String ext, System.String extgen, System.String jniExt) [0x002bb] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.Save (Xamarin.Android.Tools.ApiXmlAdjuster.JavaClass cls, System.Xml.XmlWriter writer) [0x00024] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.Save (Xamarin.Android.Tools.ApiXmlAdjuster.JavaApi api, System.Xml.XmlWriter writer) [0x000ca] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.Save (Xamarin.Android.Tools.ApiXmlAdjuster.JavaApi api, System.String xmlfile) [0x00027] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.Adjuster.Process (System.String inputXmlFile, MonoDroid.Generation.CodeGenerationOptions opt, MonoDroid.Generation.GenBase[] gens, System.String outputXmlFile, System.Int32 reportVerbosity) [0x0006f] in <63c689d575b747a0b75d77765809b60d>:0
      at Xamarin.Android.Binder.CodeGenerator.Run (Xamarin.Android.Binder.CodeGeneratorOptions options, Java.Interop.Tools.Cecil.DirectoryAssemblyResolver resolver) [0x0036a] in <63c689d575b747a0b75d77765809b60d>:0
      at Xamarin.Android.Binder.CodeGenerator.Run (Xamarin.Android.Binder.CodeGeneratorOptions options) [0x00029] in <63c689d575b747a0b75d77765809b60d>:0
      at Xamarin.Android.Binder.CodeGenerator.Main (System.String[] args) [0x00014] in <63c689d575b747a0b75d77765809b60d>:0
    [ERROR] FATAL UNHANDLED EXCEPTION: System.NullReferenceException: Object reference not set to an instance of an object
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.Save (Xamarin.Android.Tools.ApiXmlAdjuster.JavaTypeParameters typeParameters, System.Xml.XmlWriter writer, System.String indent) [0x000f0] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.SaveCommon (Xamarin.Android.Tools.ApiXmlAdjuster.JavaMember m, System.Xml.XmlWriter writer, System.String elementName, System.String abs, System.String native, System.String ret, System.String sync, System.String transient, System.String type, System.String typeGeneric, System.String value, System.String volat, Xamarin.Android.Tools.ApiXmlAdjuster.JavaTypeParameters typeParameters, System.Collections.Generic.IEnumerable`1[T] parameters, System.Collections.Generic.IEnumerable`1[T] exceptions, System.Nullable`1[T] extBridge, System.String jniReturn, System.Nullable`1[T] extSynthetic) [0x001a2] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.Save (Xamarin.Android.Tools.ApiXmlAdjuster.JavaMethod method, System.Xml.XmlWriter writer) [0x0018c] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.SaveTypeCommon (Xamarin.Android.Tools.ApiXmlAdjuster.JavaType cls, System.Xml.XmlWriter writer, System.String elementName, System.String abs, System.String ext, System.String extgen, System.String jniExt) [0x002bb] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.Save (Xamarin.Android.Tools.ApiXmlAdjuster.JavaClass cls, System.Xml.XmlWriter writer) [0x00024] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.Save (Xamarin.Android.Tools.ApiXmlAdjuster.JavaApi api, System.Xml.XmlWriter writer) [0x000ca] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.JavaApiXmlGeneratorExtensions.Save (Xamarin.Android.Tools.ApiXmlAdjuster.JavaApi api, System.String xmlfile) [0x00027] in <c382107dedd843d887cb116e53359071>:0
      at Xamarin.Android.Tools.ApiXmlAdjuster.Adjuster.Process (System.String inputXmlFile, MonoDroid.Generation.CodeGenerationOptions opt, MonoDroid.Generation.GenBase[] gens, System.String outputXmlFile, System.Int32 reportVerbosity) [0x0006f] in <63c689d575b747a0b75d77765809b60d>:0
      at Xamarin.Android.Binder.CodeGenerator.Run (Xamarin.Android.Binder.CodeGeneratorOptions options, Java.Interop.Tools.Cecil.DirectoryAssemblyResolver resolver) [0x0036a] in <63c689d575b747a0b75d77765809b60d>:0
      at Xamarin.Android.Binder.CodeGenerator.Run (Xamarin.Android.Binder.CodeGeneratorOptions options) [0x00029] in <63c689d575b747a0b75d77765809b60d>:0
      at Xamarin.Android.Binder.CodeGenerator.Main (System.String[] args) [0x00014] in <63c689d575b747a0b75d77765809b60d>:0
    /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Bindings.targets(431,5): error MSB6006: "generator.exe" exited with code 1.