iOS开发Runtime 方法替换

iOS开发Runtime 方法替换

通过#import <objc/runtime.h>我们可以找到：

 1 /**  2  * Returns a specified instance method for a given class. 3  *  4  * @param cls The class you want to inspect. 5  * @param name The selector of the method you want to retrieve. 6  *  7  * @return The method that corresponds to the implementation of the selector specified by  8  * \e name for the class specified by \e cls, or \c NULL if the specified class or its  9  * superclasses do not contain an instance method with the specified selector.10  *11  * @note This function searches superclasses for implementations, whereas \c class_copyMethodList does not.12 */13 OBJC_EXPORT Method _Nullable14 class_getInstanceMethod(Class _Nullable cls, SEL _Nonnull name)15  OBJC_AVAILABLE(10.0, 2.0, 9.0, 1.0, 2.0);

class_getInstanceMethod这个可以获取类的实例方法

#import <Foundation/Foundation.h>NS_ASSUME_NONNULL_BEGIN@interface RuntimeObjc : NSObject-(void)runEg;-(void)otherRunEg;@end

 

#import "RuntimeObjc.h"#import <objc/runtime.h>@implementation RuntimeObjc+(void)load{  Method runEg = class_getInstanceMethod(self, @selector(runEg)); Method otherRunEg = class_getInstanceMethod(self, @selector(otherRunEg));
　　//交换 method_exchangeImplementations(runEg, otherRunEg);}-(void)runEg{ NSLog(@"runEg");}-(void)otherRunEg{

　 NSLog(@"otherRunEg");

 [self otherRunEg];//已经做了置换 故调用的runEg

 
} 
@end

调用

 RuntimeObjc * objc = [[RuntimeObjc alloc]init]; [objc runEg];

 打印：

2020-05-21 15:42:43.416766+0800 11111[35733:176260] otherRunEg2020-05-21 15:42:43.416928+0800 11111[35733:176260] runEg