动态方法解析1

#import <Foundation/Foundation.h>

@interface NSPerson : NSObject

- (void)run;
+ (void)test;

@end

#import "NSPerson.h"
#import <objc/runtime.h>

@implementation NSPerson

+ (void)testImp
{
    NSLog(@"%s",__func__);
}

- (void)runImp
{
    NSLog(@"%s",__func__);
}

+ (BOOL)resolveInstanceMethod:(SEL)sel
{
    if (sel == @selector(run)) {
        Method method = class_getInstanceMethod(self, @selector(runImp));
        return  class_addMethod(self, sel, method_getImplementation(method), method_getTypeEncoding(method));

    }
    return [super resolveInstanceMethod:sel];
}

+ (BOOL)resolveClassMethod:(SEL)sel
{
    if (sel == @selector(test)) {
        Method method = class_getClassMethod(object_getClass(self),@selector(testImp) );
        return class_addMethod(object_getClass(self), sel, method_getImplementation(method), method_getTypeEncoding(method));
    }
    return [super resolveClassMethod:sel];
}

@end

#import <Foundation/Foundation.h>
#import "NSPerson.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
    
        NSPerson *person = [[NSPerson alloc] init];
        [person run];
        
        [NSPerson test];

    }
    return 0;
}

//log
2020-08-27 17:08:05.695237+0800 runtime[10652:398413] -[NSPerson runImp]
2020-08-27 17:08:05.695678+0800 runtime[10652:398413] +[NSPerson testImp]
Program ended with exit code: 0

动态方法解析2

#import <Foundation/Foundation.h>

@interface NSPerson : NSObject

- (void)run;
+ (void)test;


@end

#import "NSPerson.h"
#import <objc/runtime.h>

@implementation NSPerson

void runIMP(id self, SEL _cmd)
{
    NSLog(@"%s",__func__);
}

void testIMP(id self, SEL _cmd)
{
    NSLog(@"%s",__func__);
}

+ (BOOL)resolveInstanceMethod:(SEL)sel
{
    if (sel == @selector(run)) {
        return class_addMethod(self, sel, (IMP)runIMP, "v16@0:8");
    }
    return [super resolveInstanceMethod:sel];
}

+ (BOOL)resolveClassMethod:(SEL)sel
{
    if (sel == @selector(test)) {
        return class_addMethod(object_getClass(self), sel, (IMP)testIMP, "v16@0:8");
    }
    return [super resolveClassMethod:sel];
}

@end

#import <Foundation/Foundation.h>
#import "NSPerson.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
    
        NSPerson *person = [[NSPerson alloc] init];
        [person run];
        
        [NSPerson test];

    }
    return 0;
}

//log
2020-08-27 17:10:36.318523+0800 runtime[10680:399996] runIMP
2020-08-27 17:10:36.318962+0800 runtime[10680:399996] testIMP
Program ended with exit code: 0