ios - 使用 AssetsLibrary.h 时出错

Question

我的代码在我的源代码中如下所示:

+ (ALAssetsLibrary *)defaultAssetsLibrary {
   static dispatch_once_t pred = 0;
   static ALAssetsLibrary *library = nil;
   dispatch_once(&pred, ^{
    library = [[ALAssetsLibrary alloc] init];
    });
   return library;
}

当我尝试构建时，它给出错误:

  "_OBJC_CLASS_$_ALAssetsLibrary", referenced from:
  objc-class-ref in Setting_Main.o //Setting_Main.o reflects name of my source file          Setting_Main.h
  ld: symbol(s) not found for architecture i386

现在，当我如下注释某行时，它不显示错误。但是，我无法获得图书馆的值(value)。

+ (ALAssetsLibrary *)defaultAssetsLibrary {
   static dispatch_once_t pred = 0;
   static ALAssetsLibrary *library = nil;
   //dispatch_once(&pred, ^{
    //library = [[ALAssetsLibrary alloc] init];
   // });
   return library;
 }

谁能告诉我这里究竟出了什么问题？

Answer 1

这是链接错误，需要添加资源库

/System/Library/Frameworks/AssetsLibrary.framework

您项目的框架。