类与对象操作函数
runtime有很多的函数可以操作类和对象。类相关的是class为前缀，对象相关操作是objc或object_为前缀。
类相关操作函数
name：
// 获取类的类名
const char * class_getName ( Class cls );
super_class和meta-class:
// 获取类的父类
Class class_getSuperclass ( Class cls );
// 判断给定的Class是否是一个meta class
BOOL class_isMetaClass ( Class cls );
instance_size：
// 获取实例大小
size_t class_getInstanceSize ( Class cls );
成员变量(ivars)及属性:
//成员变量操作函数
// 获取类中指定名称实例成员变量的信息
Ivar class_getInstanceVariable ( Class cls, const char *name );
// 获取类成员变量的信息
Ivar class_getClassVariable ( Class cls, const char *name );
// 添加成员变量
BOOL class_addIvar ( Class cls, const char *name, size_t size, uint8_t alignment, const char *types ); //这个只能够向在runtime时创建的类添加成员变量
// 获取整个成员变量列表
Ivar * class_copyIvarList ( Class cls, unsigned int *outCount ); //必须使用free()来释放这个数组
//属性操作函数
// 获取类中指定名称实例成员变量的信息
Ivar class_getInstanceVariable ( Class cls, const char *name );
// 获取类成员变量的信息
Ivar class_getClassVariable ( Class cls, const char *name );
// 添加成员变量
BOOL class_addIvar ( Class cls, const char *name, size_t size, uint8_t alignment, const char *types );
// 获取整个成员变量列表
Ivar * class_copyIvarList ( Class cls, unsigned int *outCount );
methodLists：
// 添加方法
BOOL class_addMethod ( Class cls, SEL name, IMP imp, const char *types ); //和成员变量不同的是可以为类动态添加方法。如果有同名会返回NO，修改的话需要使用method_setImplementation
// 获取实例方法
Method class_getInstanceMethod ( Class cls, SEL name );
// 获取类方法
Method class_getClassMethod ( Class cls, SEL name );
// 获取所有方法的数组
Method * class_copyMethodList ( Class cls, unsigned int *outCount );
// 替代方法的实现
IMP class_replaceMethod ( Class cls, SEL name, IMP imp, const char *types );
// 返回方法的具体实现
IMP class_getMethodImplementation ( Class cls, SEL name );
IMP class_getMethodImplementation_stret ( Class cls, SEL name );
// 类实例是否响应指定的selector
BOOL class_respondsToSelector ( Class cls, SEL sel );
objc_protocol_list:
// 添加协议
BOOL class_addProtocol ( Class cls, Protocol *protocol );
// 返回类是否实现指定的协议
BOOL class_conformsToProtocol ( Class cls, Protocol *protocol );
// 返回类实现的协议列表
Protocol * class_copyProtocolList ( Class cls, unsigned int *outCount );
version:
// 获取版本号
int class_getVersion ( Class cls );
// 设置版本号
void class_setVersion ( Class cls, int version );
类和函数的使用例子
通过实例来消化下上面的那些函数：
//-----------------------------------------------------------
// MyClass.h
@interface MyClass : NSObject
@property (nonatomic, strong) NSArray *array;
@property (nonatomic, copy) NSString *string;
- (void)method1;
- (void)method2;
+ (void)classMethod1;
@end
//-----------------------------------------------------------
// MyClass.m
#import "MyClass.h"
@interface MyClass () {
NSInteger _instance1;
NSString * _instance2;
}
@property (nonatomic, assign) NSUInteger integer;
- (void)method3WithArg1:(NSInteger)arg1 arg2:(NSString *)arg2;
@end
@implementation MyClass
+ (void)classMethod1 {
}
- (void)method1 {
NSLog(@"call method method1");
}
- (void)method2 {
}
- (void)method3WithArg1:(NSInteger)arg1 arg2:(NSString *)arg2 {
NSLog(@"arg1 : %ld, arg2 : %@", arg1, arg2);
}
@end
//-----------------------------------------------------------
// main.h
#import "MyClass.h"
#import "MySubClass.h"
#import
int main(int argc, const char * argv[]) {
@autoreleasepool {
MyClass *myClass = [[MyClass alloc] init];
unsigned int outCount = 0;
Class cls = myClass.class;
// 类名
NSLog(@"class name: %s", class_getName(cls));
NSLog(@"==========================================================");
// 父类
NSLog(@"super class name: %s", class_getName(class_getSuperclass(cls)));
NSLog(@"==========================================================");
// 是否是元类
NSLog(@"MyClass is %@ a meta-class", (class_isMetaClass(cls) ? @"" : @"not"));
NSLog(@"==========================================================");
Class meta_class = objc_getMetaClass(class_getName(cls));
NSLog(@"%s's meta-class is %s", class_getName(cls), class_getName(meta_class));
NSLog(@"==========================================================");
// 变量实例大小
NSLog(@"instance size: %zu", class_getInstanceSize(cls));
NSLog(@"==========================================================");
// 成员变量
Ivar *ivars = class_copyIvarList(cls, &outCount);
for (int i = 0; i < outCount; i++) {
Ivar ivar = ivars[i];
NSLog(@"instance variable's name: %s at index: %d", ivar_getName(ivar), i);
}
free(ivars);
Ivar string = class_getInstanceVariable(cls, "_string");
if (string != NULL) {
NSLog(@"instace variable %s", ivar_getName(string));
}
NSLog(@"==========================================================");
// 属性操作
objc_property_t * properties = class_copyPropertyList(cls, &outCount);
for (int i = 0; i < outCount; i++) {
objc_property_t property = properties[i];
NSLog(@"property's name: %s", property_getName(property));
}
free(properties);
objc_property_t array = class_getProperty(cls, "array");
if (array != NULL) {
NSLog(@"property %s", property_getName(array));
}
NSLog(@"==========================================================");
// 方法操作
Method *methods = class_copyMethodList(cls, &outCount);
for (int i = 0; i < outCount; i++) {
Method method = methods[i];
NSLog(@"method's signature: %s", method_getName(method));
}
free(methods);
Method method1 = class_getInstanceMethod(cls, @selector(method1));
if (method1 != NULL) {
NSLog(@"method %s", method_getName(method1));
}
Method classMethod = class_getClassMethod(cls, @selector(classMethod1));
if (classMethod != NULL) {
NSLog(@"class method : %s", method_getName(classMethod));
}
NSLog(@"MyClass is%@ responsd to selector: method3WithArg1:arg2:", class_respondsToSelector(cls, @selector(method3WithArg1:arg2:)) ? @"" : @" not");
IMP imp = class_getMethodImplementation(cls, @selector(method1));
imp();
NSLog(@"==========================================================");
// 协议
Protocol * __unsafe_unretained * protocols = class_copyProtocolList(cls, &outCount);
Protocol * protocol;
for (int i = 0; i < outCount; i++) {
protocol = protocols[i];
NSLog(@"protocol name: %s", protocol_getName(protocol));
}
NSLog(@"MyClass is%@ responsed to protocol %s", class_conformsToProtocol(cls, protocol) ? @"" : @" not", protocol_getName(protocol));
NSLog(@"==========================================================");
}
return 0;
}
输出结果：
2014-10-22 19:41:37.452 RuntimeTest[3189:156810] class name: MyClass
2014-10-22 19:41:37.453 RuntimeTest[3189:156810] ==========================================================
2014-10-22 19:41:37.454 RuntimeTest[3189:156810] super class name: NSObject
2014-10-22 19:41:37.454 RuntimeTest[3189:156810] ==========================================================
2014-10-22 19:41:37.454 RuntimeTest[3189:156810] MyClass is not a meta-class
2014-10-22 19:41:37.454 RuntimeTest[3189:156810] ==========================================================
2014-10-22 19:41:37.454 RuntimeTest[3189:156810] MyClass's meta-class is MyClass
2014-10-22 19:41:37.455 RuntimeTest[3189:156810] ==========================================================
2014-10-22 19:41:37.455 RuntimeTest[3189:156810] instance size: 48
2014-10-22 19:41:37.455 RuntimeTest[3189:156810] ==========================================================
2014-10-22 19:41:37.455 RuntimeTest[3189:156810] instance variable's name: _instance1 at index: 0
2014-10-22 19:41:37.455 RuntimeTest[3189:156810] instance variable's name: _instance2 at index: 1
2014-10-22 19:41:37.455 RuntimeTest[3189:156810] instance variable's name: _array at index: 2
2014-10-22 19:41:37.455 RuntimeTest[3189:156810] instance variable's name: _string at index: 3
2014-10-22 19:41:37.463 RuntimeTest[3189:156810] instance variable's name: _integer at index: 4
2014-10-22 19:41:37.463 RuntimeTest[3189:156810] instace variable _string
2014-10-22 19:41:37.463 RuntimeTest[3189:156810] ==========================================================
2014-10-22 19:41:37.463 RuntimeTest[3189:156810] property's name: array
2014-10-22 19:41:37.463 RuntimeTest[3189:156810] property's name: string
2014-10-22 19:41:37.464 RuntimeTest[3189:156810] property's name: integer
2014-10-22 19:41:37.464 RuntimeTest[3189:156810] property array
2014-10-22 19:41:37.464 RuntimeTest[3189:156810] ==========================================================
2014-10-22 19:41:37.464 RuntimeTest[3189:156810] method's signature: method1
2014-10-22 19:41:37.464 RuntimeTest[3189:156810] method's signature: method2
2014-10-22 19:41:37.464 RuntimeTest[3189:156810] method's signature: method3WithArg1:arg2:
2014-10-22 19:41:37.465 RuntimeTest[3189:156810] method's signature: integer
2014-10-22 19:41:37.465 RuntimeTest[3189:156810] method's signature: setInteger:
2014-10-22 19:41:37.465 RuntimeTest[3189:156810] method's signature: array
2014-10-22 19:41:37.465 RuntimeTest[3189:156810] method's signature: string
2014-10-22 19:41:37.465 RuntimeTest[3189:156810] method's signature: setString:
2014-10-22 19:41:37.465 RuntimeTest[3189:156810] method's signature: setArray:
2014-10-22 19:41:37.466 RuntimeTest[3189:156810] method's signature: .cxx_destruct
2014-10-22 19:41:37.466 RuntimeTest[3189:156810] method method1
2014-10-22 19:41:37.466 RuntimeTest[3189:156810] class method : classMethod1
2014-10-22 19:41:37.466 RuntimeTest[3189:156810] MyClass is responsd to selector: method3WithArg1:arg2:
2014-10-22 19:41:37.467 RuntimeTest[3189:156810] call method method1
2014-10-22 19:41:37.467 RuntimeTest[3189:156810] ==========================================================
2014-10-22 19:41:37.467 RuntimeTest[3189:156810] protocol name: NSCopying
2014-10-22 19:41:37.467 RuntimeTest[3189:156810] protocol name: NSCoding
2014-10-22 19:41:37.467 RuntimeTest[3189:156810] MyClass is responsed to protocol NSCoding
2014-10-22 19:41:37.468 RuntimeTest[3189:156810] ======================================