ios google登录,如何获取用户图片网址？

我正在iOS / Swift谷歌登录.我在github上做了一个demo.
我的演示项目： https://github.com/tanggod/GoogleSignIn.git

根据谷歌(https://developers.google.com/identity/sign-in/ios/api/interface_g_i_d_profile_data#a8e229bffe211894473058c4ba247553c),用户图像网址可以像这样获取：

>(NSURL *)imageURLWithDimension：(NSUInteger)维度
获取方块每一侧的给定维度的用户配置文件图像URL(以像素为单位).

但是,当我尝试获取imageURLWithDimension(120)时,应用程序总是崩溃.我一直在为此奋斗半天,但仍然不知道为什么.
任何人都可以帮助我.非常感谢你.

func signIn(signIn: GIDSignIn!,didSignInForUser user: GIDGoogleUser!,withError error: NSError!) {
    print("=== UIViewController sign in")

    if (error == nil) {
        // Perform any operations on signed in user here.
        let userId = user.userID                  // For client-side use only!
        //let idToken = user.authentication.idToken // Safe to send to the server
        let name = user.profile.name
        let email = user.profile.email
        if user.profile.hasImage{
            // crash here !!!!!!!! cannot get imageUrl here,why?
            // let imageUrl = user.profile.imageURLWithDimension(120)
            let imageUrl = signIn.currentUser.profile.imageURLWithDimension(120)
            print(" image url: ",imageUrl.absoluteString)
        }
        // ...
        print(" userId: ",userId)
        //            print(" idToken: ",idToken)
        print(" name: ",name)
        print(" email: ",email)
        labelName.text = name
        labelEmail.text = email
    } else {
        print("\(error.localizedDescription)")
    }
}

崩溃数据如下：

2015-09-30 18:54:46.662 GoogleLogin[96614:] <GMR/INFO> App measurement v.1100000 started
2015-09-30 18:54:46.675 GoogleLogin[96614:5594982] Successfully configured [SignIn].
2015-09-30 18:54:46.675 GoogleLogin[96614:5594982] Failed to configure [].
2015-09-30 18:54:46.676 GoogleLogin[96614:5594982] Subspecs not present,so not configured [Analytics,AdMob,AppInvite,CloudMessaging,Maps].
2015-09-30 18:54:46.676 GoogleLogin[96614:5594982] Subspecs expected to be present [SignIn,Measurement].
2015-09-30 18:54:46.706 GoogleLogin[96614:] <GMR/INFO> Network status has changed. code,status: 2,Connected
=== UIViewController sign in
2015-09-30 18:54:49.335 GoogleLogin[96614:5594982] -[NSURL isFIFEUrl]: unrecognized selector sent to instance 0x7fe248c335c0
2015-09-30 18:56:46.968 GoogleLogin[96614:5594982] -[NSURL isFIFEUrl]: unrecognized selector sent to instance 0x7fe248f11f20
2015-09-30 18:56:46.973 GoogleLogin[96614:5594982] *** Terminating app due to uncaught exception 'NSinvalidargumentexception',reason: '-[NSURL isFIFEUrl]: unrecognized selector sent to instance 0x7fe248f11f20'
*** First throw call stack:
(
    0   CoreFoundation                      0x0000000102304f65 __exceptionPreprocess + 165
    1   libobjc.A.dylib                     0x0000000104927deb objc_exception_throw + 48
    2   CoreFoundation                      0x000000010230d58d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
    3   CoreFoundation                      0x000000010225af7a ___forwarding___ + 970
    4   CoreFoundation                      0x000000010225ab28 _CF_forwarding_prep_0 + 120
    5   GoogleLogin                         0x0000000101db6214 -[GIDProfileData imageURLWithDimension:] + 75
    6   GoogleLogin                         0x0000000101d29d0d _TFC11GoogleLogin14ViewController6signInfS0_FTGSQCSo9GIDSignIn_16didSignInForUserGSQCSo13GIDGoogleUser_9withErrorGSQCSo7NSError__T_ + 2541
    7   GoogleLogin                         0x0000000101d2aa98 _TToFC11GoogleLogin14ViewController6signInfS0_FTGSQCSo9GIDSignIn_16didSignInForUserGSQCSo13GIDGoogleUser_9withErrorGSQCSo7NSError__T_ + 88
    8   GoogleLogin                         0x0000000101dbdeb8 __37-[GIDSignIn addCallDelegateCallback:]_block_invoke + 123
    9   GoogleLogin                         0x0000000101db5ab6 -[GIDCallbackQueue fire] + 147
    10  GoogleLogin                         0x0000000101dbdacb __38-[GIDSignIn addDecodeIdTokenCallback:]_block_invoke_2 + 385
    11  libdispatch.dylib                   0x00000001053eaef9 _dispatch_call_block_and_release + 12
    12  libdispatch.dylib                   0x000000010540b49b _dispatch_client_callout + 8
    13  libdispatch.dylib                   0x00000001053f334b _dispatch_main_queue_callback_4CF + 1738
    14  CoreFoundation                      0x00000001022653e9 __CFRUNLOOP_IS_SERVICING_THE_MAIN_disPATCH_QUEUE__ + 9
    15  CoreFoundation                      0x0000000102226939 __CFRunLoopRun + 2073
    16  CoreFoundation                      0x0000000102225e98 CFRunLoopRunSpecific + 488
    17  GraphicsServices                    0x00000001066b5ad2 GSEventRunModal + 161
    18  UIKit                               0x00000001034b0676 UIApplicationMain + 171
    19  GoogleLogin                         0x0000000101d2c36d main + 109
    20  libdyld.dylib                       0x000000010543f92d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)

并且它表示signIn.currentUser.profile.imageURLWithDimension(120)是无效的表达式：

#import <Foundation/Foundation.h>

@interface NSURL (FILE)
- (BOOL) isFIFEUrl;
@end

@implementation  NSURL (FILE)
- (BOOL) isFIFEUrl {
    return [self isFileURL];
}

@end