RUNTIME替换类方法

/*

memberMethod:是否成员方法

*/

void swizzleMethod(Class class,SEL originalSelector,SEL swizzledSelector,BOOL memberMethod) {

    Method originalMethod ;

    Method swizzledMethod;

    if( memberMethod ) {

        originalMethod =class_getInstanceMethod(class, originalSelector);

        swizzledMethod =class_getInstanceMethod(class, swizzledSelector);

    }else{

        class =object_getClass(class);// <------修改

        originalMethod =class_getClassMethod(class, originalSelector);

        swizzledMethod =class_getClassMethod(class, swizzledSelector);

    }

    IMP swizzledImp =method_getImplementation(swizzledMethod);

    char* swizzledTypes = (char*)method_getTypeEncoding(swizzledMethod);

    IMP originalImp =method_getImplementation(originalMethod);

    char* originalTypes = (char*)method_getTypeEncoding(originalMethod);

    BOOL success =class_addMethod(class, originalSelector, swizzledImp, swizzledTypes);

    if(success) {

        class_replaceMethod(class, swizzledSelector, originalImp, originalTypes);

    }else{

        // 添加失败，表明已经有这个方法，直接交换

        method_exchangeImplementations(originalMethod, swizzledMethod);

    }

}