Objective-c类运行时定义 [英] Objective-c Classes runtime definition
本文介绍了Objective-c类运行时定义的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
是否可以在objective-c中的运行时定义类?
例如我收到一个XML文件,它定义一个对象并创建它并在运行时使用它?
Is it possible to define classes at run time in objective-c?
E.g. I receive an XML file, that defines an object and create it and use it in run-time?
推荐答案
是的,检查一下代码片段,我在这里创建了一个类,只使用C方法和一个协议定义(为了简化消息调用)...
Yes, check this code snippet out, I created a class here, using only C methods, and one protocol definition (for simplicity when making message calls)...
MyCObject.h
MyCObject.h
#import <Foundation/Foundation.h>
@protocol MyCObj_methods<NSObject>
-(NSString *) getString;
-(int) getInt;
+(NSString *) someStaticMethod;
@end
typedef id<MyCObj_methods> MyCObj;
extern Class MyCObj_class;
__attribute__((constructor))
void MyCObj_initialize();
MyCObj MyCObj_alloc( id self, SEL _cmd );
MyCObj MyCObj_new( id self, SEL _cmd );
NSString *MyCObj_someStaticMethod ( id self, SEL _cmd );
MyCObj MyCObj_init( MyCObj self, SEL _cmd );
NSString *MyCObj_getString( MyCObj self, SEL _cmd );
int MyCObj_getInt( MyCObj self, SEL _cmd );
MyCObject.m
MyCObject.m
#import "MyCObject.h"
#import <objc/Object.h>
#import <objc/runtime.h>
static Class myStaticClass;
Class MyCObj_class;
typedef struct
{
Class isa;
NSString *myString;
int myInt;
} MyCObj_t;
void MyCObj_initialize(void);
__attribute__((constructor))
void MyCObj_initialize()
{
MyCObj_class = objc_allocateClassPair([NSObject class], "MyCObj", 0);
objc_registerClassPair(MyCObj_class);
myStaticClass = object_getClass(MyCObj_class);
class_addMethod(MyCObj_class, @selector(init), (IMP)MyCObj_init, "@@:");
class_addMethod(MyCObj_class, @selector(getString), (IMP)MyCObj_getString, "@@:");
class_addMethod(MyCObj_class, @selector(getInt), (IMP)MyCObj_getInt, "i@:");
class_addMethod(myStaticClass, @selector(alloc), (IMP)MyCObj_alloc, "@@:");
class_addMethod(myStaticClass, @selector(new), (IMP)MyCObj_new, "@@:");
class_addMethod(myStaticClass, @selector(someStaticMethod), (IMP)MyCObj_someStaticMethod, "@@:");
}
MyCObj MyCObj_alloc(id self, SEL _cmd)
{
return (MyCObj) class_createInstance(MyCObj_class, sizeof(MyCObj_t) - sizeof(Class));
}
MyCObj MyCObj_new(id self, SEL _cmd)
{
return (MyCObj) [[MyCObj_class alloc] init];
}
NSString *MyCObj_someStaticMethod(id self, SEL _cmd)
{
return @"Some Static Method";
}
MyCObj MyCObj_init(MyCObj self, SEL _cmd)
{
struct objc_super super = { .receiver = self, .super_class = [NSObject class] };
if ((self = (MyCObj) objc_msgSendSuper(&super, _cmd)))
{
((MyCObj_t *) self)->myString = @"hello world!";
((MyCObj_t *) self)->myInt = 15;
}
return self;
}
NSString *MyCObj_getString(MyCObj self, SEL _cmd)
{
return ((MyCObj_t *) self)->myString;
}
int MyCObj_getInt(MyCObj self, SEL _cmd)
{
return ((MyCObj_t *) self)->myInt;
}
用法:
MyCObj obj = [MyCObj_class new];
NSLog(@"%@ %i %@", [obj getString], [obj getInt], [MyCObj_class someStaticMethod]);
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