iOS无CocoaPods集成Firebase ML Kit时GoogleMobileVision链接错误

问题描述 #

我正尝试在不使用CocoaPods的Xcode项目中集成Firebase 5.0.1的MLVisionTextModel，已按照Readme.md文件添加所有依赖框架，但出现以下链接错误：

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"OBJC_CLASS$_LAContext", referenced from:
objc-class-ref in GoogleMobileVision(MDMPasscodeCache_f189776e75765630b82721fafea64052.o)
"_vImageConverter_CreateWithCGImageFormat", referenced from:
+[GMVUtility(Internal) sampleBuffer32BGRATo32RGBA:] in GoogleMobileVision(GMVUtility+Internal_1a3089c1f18dbb4046735909972b8cb2.o)
"_vImageConvert_AnyToAny", referenced from:
+[GMVUtility(Internal) sampleBuffer32BGRATo32RGBA:] in GoogleMobileVision(GMVUtility+Internal_1a3089c1f18dbb4046735909972b8cb2.o)
"_vImageConverter_Release", referenced from:
+[GMVUtility(Internal) sampleBuffer32BGRATo32RGBA:] in GoogleMobileVision(GMVUtility+Internal_1a3089c1f18dbb4046735909972b8cb2.o)
"_vImageBuffer_InitWithCGImage", referenced from:
+[GMVUtility(Internal) rgbaPixelDataFromCGImage:] in GoogleMobileVision(GMVUtility+Internal_1a3089c1f18dbb4046735909972b8cb2.o)
"_vImageRotate_ARGB8888", referenced from:
+[GMVUtility(Internal) rotatePixelData:width:height:bytesPerRow:withAngle:] in GoogleMobileVision(GMVUtility+Internal_1a3089c1f18dbb4046735909972b8cb2.o)
"_vImageHorizontalReflect_ARGB8888", referenced from:
+[GMVUtility(Internal) flipRGBA8888Horizontally:width:height:bytesPerRow:] in GoogleMobileVision(GMVUtility+Internal_1a3089c1f18dbb4046735909972b8cb2.o)
"_vImagePermuteChannels_ARGB8888", referenced from:
+[GMVUtility(Internal) permutate:width:height:bytesPerRow:order:] in GoogleMobileVision(GMVUtility+Internal_1a3089c1f18dbb4046735909972b8cb2.o)
"_vImageFlatten_RGBA8888ToRGB888", referenced from:
+[GMVUtility(Internal) flattenRGBA8888ToRGB888:width:height:bytesPerRow:] in GoogleMobileVision(GMVUtility+Internal_1a3089c1f18dbb4046735909972b8cb2.o)
ld: symbol(s) not found for architecture x86_64

问题分析 #

这些错误都是因为项目缺少了两个GoogleMobileVision依赖的系统框架：

• _OBJC_CLASS_$_LAContext 来自 LocalAuthentication.framework：这个框架用于处理设备密码验证相关逻辑，GoogleMobileVision的密码缓存模块用到了它
• 所有vImage*开头的符号来自 Accelerate.framework：这是苹果提供的高性能计算框架，GoogleMobileVision用它来处理图像的转换、旋转、通道排列等操作

解决步骤 #

1. 打开你的Xcode项目，选中需要集成的目标(target)
2. 切换到Build Phases标签页
3. 找到并展开Link Binary With Libraries选项
4. 点击列表下方的+按钮，在搜索框中分别搜索并添加：
   • LocalAuthentication.framework
   • Accelerate.framework
5. 完成添加后，重新编译你的项目，这些链接错误应该就能被解决了

手动集成第三方库时，经常会遇到这种隐式依赖的系统框架缺失问题，毕竟CocoaPods会自动帮我们处理这些依赖关系，手动操作就得自己排查这类符号缺失的问题啦。

内容的提问来源于stack exchange，提问作者avdhut