創(chuàng)建NSNotificationCenter的子類

@interface MyNotificationCenter : NSNotificationCenter

@end

@implementation MyNotificationCenter

+ (void)load {
    Method origin = class_getInstanceMethod([self class],@selector(removeObserver:));
    Method current = class_getInstanceMethod([self class],@selector(_removeObserver:));
    method_exchangeImplementations(origin, current);
}

- (void)_removeObserver:(id)observer {
    NSLog(@"調用移除通知方法: %@",observer);
    //[self _removeObserver:observer];
}

@end

當VC被釋放時，即使我們不在dealloc中寫

-(void)dealloc{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

我們的Log依然會觸發(fā)，且可以在log中找到vc對象