我阅读了article about "Method Swizzling in Objective-C"。在本文中,“方法Swizzing”的含义是交换两种方法的实现。样品是如下所示:Objective-C中的方法Swizzling
- (void) logged_viewDidAppear:(BOOL)animated {
[self logged_viewDidAppear:animated];
NSLog(@"logged view did appear for %@", [self class]);
}
+ (void)load {
static dispatch_once_t once_token;
dispatch_once(&once_token, ^{
SEL viewWillAppearSelector = @selector(viewDidAppear:);
SEL viewWillAppearLoggerSelector = @selector(logged_viewDidAppear:);
Method originalMethod = class_getInstanceMethod(self, viewWillAppearSelector);
Method extendedMethod = class_getInstanceMethod(self, viewWillAppearLoggerSelector);
method_exchangeImplementations(originalMethod, extendedMethod);
});
}
- (void) logged_viewDidAppear:(BOOL)animated {
[self logged_viewDidAppear:animated];
NSLog(@"logged view did appear for %@", [self class]);
}
在这篇文章中,一个句子是
它可能看起来这这种方法使得对自身的无意义的递归调用,但它实际上并不会那么做我们调整它之后。
但我不会因为这个声明很清楚,这是否意味着,当我们写的代码象下面这样:
[self viewDidAppear],
,因为它的实现成为“logged_viewDidAppear”,所以程序转到方法“ logged_viewDidAppear“,在该方法中,我们可以看到,第一行是[self logged_viewDidAppear:animated];出于同样的原因,该方法变成“viewDidAppear”。我的话是正确的吗?