I'm getting compiler warnings with AFNetworkin

问题:

I'm using the most excellent AFNetworking library in a project that I'm currently upgrading to iOS 6. I'm in the middle of the upgrade, whittling down the bunch of warnings that I get when compiling against the iOS 6 SDK.

AFNetworking gives me two warnings in all targets:

SystemConfiguration framework not found in project, or not included in
precompiled header. Network reachability functionality will not be available.

and

MobileCoreServices framework not found in project, or not included in
precompiled header. Automatic MIME type detection when uploading files
in multipart requests will not be available.

Here's the thing, though: those two libraries are added in all my targets. I'd like to get rid of those warnings the proper way; I won't modify the AFNetworking files. I suspect it's Xcode being silly. It's admittedly a small thing, but leaving warnings around is bad practice.

How can I remove those warnings?

I've tried restarting Xcode and cleaning. Both don't work.

回答1:

I'm not sure if you're using CocoaPods or not but this is a known issue being tracked on the AFNetworking Github page.

I was able to fix this by adding the correct import statements directly to my `PROJECTNAME-Prefix.pch there I changed it to this.

#ifdef __OBJC__
  #import <UIKit/UIKit.h>
  #import <SystemConfiguration/SystemConfiguration.h>
  #import <MobileCoreServices/MobileCoreServices.h>
#endif

If you have something else in there don't delete it. Just add the imports for SystemConfiguration and MobileCoreServices.

For OS X:

#ifdef __OBJC__
    #import <Cocoa/Cocoa.h>
    #import <SystemConfiguration/SystemConfiguration.h>
    #import <CoreServices/CoreServices.h>
#endif

回答2:

If you're using swift: Xcode compiles Swift code before the Prefix.pch file is compiled, so you'll get these warnings even if the correct imports are in your .pch file. The best solution I've found is to add them to the project's Bridging-Header.h file before importing AFNetworking:

#import <SystemConfiguration/SystemConfiguration.h>
#import <MobileCoreServices/MobileCoreServices.h>
#import "AFNetworking.h"

回答3:

This has already been answered, but still, if you're developing a command line tool potentially to be compiled for both OS X and iOS (not App Store for sure), you can add this:

#ifdef __OBJC__
    #import <Foundation/Foundation.h>
    #import <SystemConfiguration/SystemConfiguration.h>

    #if TARGET_OS_IPHONE
        #import <MobileCoreServices/MobileCoreServices.h>
    #elif TARGET_OS_MAC
        #import <CoreServices/CoreServices.h>
    #endif

#endif

By evaluating the target you're compiling to, it will include the proper files.