解决symbol(s) not found for architecture x86_64报错

今天在引入一个第三方的拍照选择照片的库时，编译报错。
Undefined symbols for architecture x86_64:  "_ALAssetPropertyAssetURL", referenced from:      -[TZImageManager getAssetIdentifier:] in TZImageManager.o  "_ALAssetPropertyDuration", referenced from:      ___90-[TZImageManager getAssetsFromFetchResult:allowPickingVideo:allowPickingImage:completion:]_block_invoke139 in TZImageManager.o      ___97-[TZImageManager getAssetFromFetchResult:atIndex:allowPickingVideo:allowPickingImage:completion:]_block_invoke in TZImageManager.o  "_ALAssetPropertyType", referenced from:      ___90-[TZImageManager getAssetsFromFetchResult:allowPickingVideo:allowPickingImage:completion:]_block_invoke139 in TZImageManager.o      ___97-[TZImageManager getAssetFromFetchResult:atIndex:allowPickingVideo:allowPickingImage:completion:]_block_invoke in TZImageManager.o  "_ALAssetPropertyURLs", referenced from:      -[TZImageManager getVideoWithAsset:completion:] in TZImageManager.o      -[TZImageManager isAssetsArray:containAsset:] in TZImageManager.o  "_ALAssetTypeVideo", referenced from:      ___90-[TZImageManager getAssetsFromFetchResult:allowPickingVideo:allowPickingImage:completion:]_block_invoke139 in TZImageManager.o      ___97-[TZImageManager getAssetFromFetchResult:atIndex:allowPickingVideo:allowPickingImage:completion:]_block_invoke in TZImageManager.o  "_ALAssetsGroupPropertyName", referenced from:      ___66-[TZImageManager getCameraRollAlbum:allowPickingImage:completion:]_block_invoke in TZImageManager.o      ___60-[TZImageManager getAllAlbums:allowPickingImage:completion:]_block_invoke in TZImageManager.o  "_OBJC_CLASS_$_ALAsset", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_ALAssetsFilter", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_ALAssetsGroup", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_ALAssetsLibrary", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHAsset", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHAssetCollection", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHAssetCreationRequest", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHAssetResourceCreationOptions", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHCachingImageManager", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHFetchOptions", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHFetchResult", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHImageManager", referenced from:      objc-class-ref in TZAssetCell.o      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHImageRequestOptions", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHPhotoLibrary", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHVideoRequestOptions", referenced from:      objc-class-ref in TZImageManager.o  "_PHImageCancelledKey", referenced from:      ___58-[TZImageManager getPhotoWithAsset:photoWidth:completion:]_block_invoke in TZImageManager.o      ___55-[TZImageManager getOriginalPhotoWithAsset:completion:]_block_invoke in TZImageManager.o  "_PHImageErrorKey", referenced from:      ___58-[TZImageManager getPhotoWithAsset:photoWidth:completion:]_block_invoke in TZImageManager.o      ___55-[TZImageManager getOriginalPhotoWithAsset:completion:]_block_invoke in TZImageManager.o  "_PHImageManagerMaximumSize", referenced from:      -[TZImageManager getOriginalPhotoWithAsset:completion:] in TZImageManager.o  "_PHImageResultIsDegradedKey", referenced from:      ___58-[TZImageManager getPhotoWithAsset:photoWidth:completion:]_block_invoke in TZImageManager.o      ___58-[TZImageManager getPhotoWithAsset:photoWidth:completion:]_block_invoke_2 in TZImageManager.o  "_PHImageResultIsInCloudKey", referenced from:      ___58-[TZImageManager getPhotoWithAsset:photoWidth:completion:]_block_invoke in TZImageManager.old: symbol(s) not found for architecture x86_64clang: error: linker command failed with exit code 1 (use -v to see invocation)
经过几个小时的查资料，和尝试，基本上确定了是由于部分依赖的框架没有导入（天知道为什么会没有导入，我在另一个项目里面直接拖进去就可以编译的，坑爹的xcode）。
于是我仔细看了下报错的内容，都是指向TZImageManager，于是我到对应的.m文件里面，发现它引用了系统的AssetsLibrary框架：

屏幕快照 2016-07-01 16.41.07.png
我尝试手动导入这个框架:

屏幕快照 2016-07-01 16.45.05.png
编译一下，原来报27个错，现在只有17个了，看来有效果。于是我继续找还缺少了什么框架。现在的报错如下：
Undefined symbols for architecture x86_64:  "_OBJC_CLASS_$_PHAsset", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHAssetCollection", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHAssetCreationRequest", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHAssetResourceCreationOptions", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHCachingImageManager", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHFetchOptions", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHFetchResult", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHImageManager", referenced from:      objc-class-ref in TZAssetCell.o      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHImageRequestOptions", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHPhotoLibrary", referenced from:      objc-class-ref in TZImageManager.o  "_OBJC_CLASS_$_PHVideoRequestOptions", referenced from:      objc-class-ref in TZImageManager.o  "_PHImageCancelledKey", referenced from:      ___58-[TZImageManager getPhotoWithAsset:photoWidth:completion:]_block_invoke in TZImageManager.o      ___55-[TZImageManager getOriginalPhotoWithAsset:completion:]_block_invoke in TZImageManager.o  "_PHImageErrorKey", referenced from:      ___58-[TZImageManager getPhotoWithAsset:photoWidth:completion:]_block_invoke in TZImageManager.o      ___55-[TZImageManager getOriginalPhotoWithAsset:completion:]_block_invoke in TZImageManager.o  "_PHImageManagerMaximumSize", referenced from:      -[TZImageManager getOriginalPhotoWithAsset:completion:] in TZImageManager.o  "_PHImageResultIsDegradedKey", referenced from:      ___58-[TZImageManager getPhotoWithAsset:photoWidth:completion:]_block_invoke in TZImageManager.o      ___58-[TZImageManager getPhotoWithAsset:photoWidth:completion:]_block_invoke_2 in TZImageManager.o  "_PHImageResultIsInCloudKey", referenced from:      ___58-[TZImageManager getPhotoWithAsset:photoWidth:completion:]_block_invoke in TZImageManager.old: symbol(s) not found for architecture x86_64clang: error: linker command failed with exit code 1 (use -v to see invocation)
当时在看这个报错的时候，一头雾水，PHxxx的库根本找不到，于是在.m里面找，半天之后猜是不是Photos框架，导入了之后编译成功！
猜得很艰辛啊。
现在写这个文章的时候，突然发现对应的TZImageManager.h文件里果然导入了Photos框架……

屏幕快照 2016-07-01 16.53.18.png

猜得那么辛苦，原来.h里面就有答案，醉了。
解决这个问题花了一个下午的时间，写一篇文章做个备份，免得下次又被坑。