why can't hook viewDidLoad (UIViewController) ??

[wangqianjun]

Hi Steipete, why can't hook viewDidLoad (UIViewController) ??
Error: Aspects: Blog signature <NSMethodSignature: 0x7fbc8bd35740> doesn't match <NSMethodSignature: 0x7fbc8bf0cc40>.

Please help~

Thank u.

[steipete]

Hi, if you post some code I can help.

[wangqianjun]

Steipete, I create a Category for UIViewcontroller, and have a Class method viewDidloadLogging:

• (void)viewDidloadLogging { [UIViewController aspect_hookSelector:@selector(viewDidLoad) withOptions:AspectPositionAfter usingBlock:^(idaspectInfo, BOOL animated){ NSLog(@"View Controller %@ will appear animated: %tu", [aspectInfo.instance class], animated); NSLog(@"arguments:%@",[aspectInfo arguments]); NSLog(@"originalInvocation:%@",[aspectInfo originalInvocation]); } error:NULL]; }

In my demo AppDelegate,

• (BOOL)application:(UIApplication )application didFinishLaunchingWithOptions:(NSDictionary )launchOptions { // Override point for customization after application launch. [UIViewController viewDidloadLogging]; return YES; }

There are no problems using？

[hustlzp]

+1

[steipete]

+1's don't help. Somebody who digs in and figures out what fails would help though. Thanks!

[wangqianjun]

So that question answer is what，Steipete？^.^

[xiaochaoren]

This is the problem of execution order of [UIViewController viewDidLoad] and [UIViewController viewDidloadLogging]. Please make sure [UIViewController viewDidloadLogging] is invoked before [UIViewController viewDidLoad].

[Freeway1979]

I got the same issue while hooking viewDidLoad selector of UIViewController class. I can't call the block I provided but "dealloc" is working.

Can you figure out the solution?

Thanks a lot.

The code as following:

• (BOOL)application:(UIApplication )application didFinishLaunchingWithOptions:(NSDictionary )launchOptions { // Ignore hooks when we are testing. if (!NSClassFromString(@"XCTestCase")) { [[LogManager sharedInstance] logViewControllerLifeCycle]; } //...other code
  }

• (void)logViewControllerLifeCycle { [UIViewController aspect_hookSelector:@selector(viewDidLoad) withOptions:AspectPositionBefore usingBlock:^(id info, BOOL animated) { UIViewController controller = [info instance]; NSString key = NSStringFromClass([controller class]); NSInteger refCount = [[self.dicViewControllerRefCount objectForKey:key] integerValue]; refCount++; [self.dicViewControllerRefCount setObject:[NSString smc_stringFromInteger:refCount] forKey:key]; NSLog(@"%s %@ viewDidLoad",FUNCTION,key); NSLog(@"%s alloc %@,%ld",FUNCTION,key,refCount); } error:NULL]; //...other code
  }

[Freeway1979]

Hi everyone, I made it. The root cause is that "aspect_isCompatibleBlockSignature" verifies that argument count of blockSignature and methodSignature,and if not matched ,nil returned. You can see these code : if (blockSignature.numberOfArguments > methodSignature.numberOfArguments) { signaturesMatch = NO; //You will go here if wrong block parameters provided as above. }else {

Now ,we can correct it by changing [UIViewController aspect_hookSelector:@selector(viewDidLoad) withOptions:AspectPositionBefore usingBlock:^(id info, BOOL animated) { to [UIViewController aspect_hookSelector:@selector(viewDidLoad) withOptions:AspectPositionBefore usingBlock:^(id info) {

It works now for "viewDidLoad".

Hi @Steipete, I suggest to throw an exception here for developers to correct it to right things.

Thanks.

[ApesTalk]

How can i use AspectPositionInstead option replace viewDidLoad method? Any help would be appreciated.

[MySubViewController aspect_hookSelector:@selector(viewDidLoad) withOptions:AspectPositionInstead usingBlock:^(id info){ //How can i use super here ??? // [super viewDidLoad]; WTSubViewController vc = (WTSubViewController )info.instance; vc.view.backgroundColor = [UIColor blueColor]; } error:NULL];