IOS Swizzle (Hook)

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#import "Nsarray+swizzle.h"

@implementation Nsarray (Swizzle)

-(ID) mylastobject

{

ID ret = [ self mylastobject];

NSLog(@ "-----mylastobject-------");

return ret;

}

@end

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#import "Nsarray+swizzle.h"

#import <objc/runtime.h>

Method ori = class_getinstancemethod([nsarray class], @selector( Lastobject));

Method new = Class_getinstancemethod([nsarray class], @selector( Mylastobject));

method_exchangeimplementations(ori, new);

nsarray * array = @[@ "0",@ "1",@ "2",@ "3"];

nsstring * str = [array lastobject];

NSLog (@ "str:%@", str);

Output

-----mylastobject-------

Str:3

Explanation: The above code will be lastobject with Mylastobject.

So [array Lastobject] This sentence call should be mylastobject, and mylastobject inside call Mylastobject is actually called Lastobject.