做国际化的app, google登录是一定少不了的, 今天介绍一种google登录引起的崩溃.

先看堆栈

Thread 0 (crashed)
 0  CoreFoundation!__exceptionPreprocess + 0x7c
    Found by: given as instruction pointer in context
 1  libobjc.A.dylib!objc_exception_throw + 0x34
    Found by: previous frame's frame pointer
 2  CoreFoundation!+[NSException raise:format:] + 0x70
    Found by: previous frame's frame pointer
 3  Hago!-[GIDSignIn assertValidUIDelegate] + 0xc8
    Found by: previous frame's frame pointer
 4  Hago!-[GIDSignIn signInWithOptions:] + 0x5c
    Found by: previous frame's frame pointer
 5  Hago!-[GIDSignIn signIn] + 0x44
    Found by: previous frame's frame pointer
 6  Hago!-[HGTpLoginMgr login:timeout:] [PKTpLoginMgr.m : 68 + 0x10]
    Found by: previous frame's frame pointer
 7  Hago!-[HGLoginModule thirdpartyLogin:bindToGuestIfNeed:callback:timeout:] [PKLoginModule.m : 382 + 0x14]
    Found by: previous frame's frame pointer
 8  Hago!-[HGLoginModule thirdpartyLogin:callback:timeout:] [PKLoginModule.m : 363 + 0x1c]
    Found by: previous frame's frame pointer
 9  Hago!-[HGLoginUIService thiredpartyLoginWithThirdpartType:successCallback:failureCallbakc:] [PKLoginUIService.m : 75 + 0x1c]
    Found by: previous frame's frame pointer
10  Hago!-[HGPopupLoginOtherWaysAlertContentView loginWithType:] [MFPopupLoginOtherWaysAlertContentView.m : 120 + 0xc]
    Found by: previous frame's frame pointer
11  Hago!__50-[HGPopupLoginOtherWaysAlertContentView viewInit:]_block_invoke.107 [MFPopupLoginOtherWaysAlertContentView.m : 92 + 0x4]
    Found by: previous frame's frame pointer
12  Hago!-[UIControl(Block) callActionBlock:] [UIControl+Block.m : 26 + 0x8]
    Found by: previous frame's frame pointer
13  UIKit!-[UIApplication sendAction:to:from:forEvent:] + 0x5c
    Found by: previous frame's frame pointer
14  UIKit!-[UIControl sendAction:to:forEvent:] + 0x4c
    Found by: previous frame's frame pointer
15  Hago!-[UIButton(touch) mySendAction:to:forEvent:] [UIButton+touch.m : 93 + 0x18]
    Found by: previous frame's frame pointer
16  UIKit!-[UIControl _sendActionsForEvents:withEvent:] + 0x1b4
    Found by: previous frame's frame pointer
17  UIKit!-[UIControl touchesEnded:withEvent:] + 0x23c
    Found by: previous frame's frame pointer
18  Hago!-[HGButton touchesEnded:withEvent:] [PKButton.m : 27 + 0x24]
    Found by: previous frame's frame pointer
19  UIKit!-[UIWindow _sendTouchesForEvent:] + 0x9ec
    Found by: previous frame's frame pointer
20  UIKit!-[UIWindow sendEvent:] + 0xc84
    Found by: previous frame's frame pointer
21  Hago!-[HiidoSDKCht sendEvent1:] [HiidoSDKCht.m : 121 + 0x10]
    Found by: previous frame's frame pointer
22  UIKit!-[UIApplication sendEvent:] + 0x150
    Found by: previous frame's frame pointer
23  UIKit!__dispatchPreprocessedEventFromEventQueue + 0x938
    Found by: previous frame's frame pointer
24  UIKit!__handleEventQueueInternal + 0x1294
    Found by: previous frame's frame pointer
25  UIKit!__handleHIDEventFetcherDrain + 0x94
    Found by: previous frame's frame pointer
26  CoreFoundation!__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 0x14
    Found by: previous frame's frame pointer
27  CoreFoundation!__CFRunLoopDoSource0 + 0x54
    Found by: previous frame's frame pointer
28  CoreFoundation!__CFRunLoopDoSources0 + 0xc8
    Found by: previous frame's frame pointer
29  CoreFoundation!__CFRunLoopRun + 0x414
    Found by: previous frame's frame pointer
30  CoreFoundation!CFRunLoopRunSpecific + 0x1b0
    Found by: previous frame's frame pointer
31  GraphicsServices!GSEventRunModal + 0x60
    Found by: previous frame's frame pointer
32  UIKit!UIApplicationMain + 0xcc
    Found by: previous frame's frame pointer
33  Hago!main [main.mm : 18 + 0x10]
    Found by: previous frame's frame pointer
34  libdyld.dylib!start + 0x0
    Found by: previous frame's frame pointer

在过去30天这个崩溃只发生了一次, WTF, 概率这么小? 但还是要修复, 因为这个崩溃挺好重现的, 只是我们的业务场景规避了崩溃的情况, 从崩溃堆栈上看崩溃发生在[GIDSignIn assertValidUIDelegate], 这个是谷歌登录内部的方法, 由于我们使用的是谷歌的静态库(.framework), 这里关于GIDSignIn类如何实现并没有暴露出来, 我们继续看崩溃的原因:

08-12 18:47:33.581 Handle Exception:
08-12 18:47:33.586 Exception Name: NSInvalidArgumentException
08-12 18:47:33.591 Exception Reason: uiDelegate must either be a |UIViewController| or implement the |signIn:presentViewController:| and |signIn:dismissViewController:| methods from |GIDSignInUIDelegate|.

之前我们的代码是在HGLoginViewController设置的uiDelegate, 但是从日志上看, 崩溃的时候HGLoginViewController已经dealloc了, 所以崩溃并不奇怪.

崩溃的原因是说uiDelegate必须是UIViewController或者实现GIDSignInUIDelegate代理, 在代码中, 我们是这样进行初始化的.

HGGoogleLoginMgr.h
@interface HGGoogleLoginMgr : NSObject <GIDSignInUIDelegate>

@end

HGGoogleLoginMgr.m
- (instancetype)init
{
    if (self = [super init]) {
        NSString *clientID = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"G_CLIENT_ID"];
        _signInMgr = [GIDSignIn sharedInstance];
        _signInMgr.clientID = clientID;
        _signInMgr.delegate = self;
        _signInMgr.uiDelegate = self;
        _signInMgr.shouldFetchBasicProfile = YES;
    }
    return self;
}

我们初始化的时候就把uiDelegate写死了, 而且在整个运行期, HGGoogleLoginMgr的实例并不会释放, 这样就可以了. 然后再实现代理:

- (void)signInWillDispatch:(GIDSignIn *)signIn error:(NSError *)error
{
}

// Present a view that prompts the user to sign in with Google
- (void)signIn:(GIDSignIn *)signIn presentViewController:(UIViewController *)viewController
{
    UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;
    while (topController.presentedViewController) {
        topController = topController.presentedViewController;
    }
    [topController presentViewController:viewController animated:YES completion:nil];
}

// Dismiss the "Sign in with Google" view
- (void)signIn:(GIDSignIn *)signIn dismissViewController:(UIViewController *)viewController
{
    UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;
    while (topController.presentedViewController) {
        topController = topController.presentedViewController;
    }
    [topController dismissViewControllerAnimated:YES completion:nil];
}

还有一种解法, 因为我们所有的控制器都是基于导航控制器的, 所以, 在每次调用signIn前都可以去设置一下当前的uiDelegate

- (void)tp_login:(PKTpLoginCallback)callback timeout:(TimeOutHandler)timeout
{
    _loginCallback = callback;
    _signInMgr.uiDelegate = (id<GIDSignInUIDelegate>)[UIApplication sharedApplication].keyWindow.rootViewController;
    [_signInMgr signOut];
    [_signInMgr signIn];
}

这样在我们的导航控制器中实现代理就OK了

- (void)signInWillDispatch:(GIDSignIn *)signIn error:(NSError *)error
{
}
// Present a view that prompts the user to sign in with Google
- (void)signIn:(GIDSignIn *)signIn presentViewController:(UIViewController *)viewController
{
    [self presentViewController:viewController animated:YES completion:nil];
}

// Dismiss the "Sign in with Google" view
- (void)signIn:(GIDSignIn *)signIn dismissViewController:(UIViewController *)viewController
{
    [self dismissViewControllerAnimated:YES completion:nil];
}

这样我们只要app还在, 那根控制器必然存在, 这时候设置的uiDelegate是不会为nil的, 就不会有崩溃了.