标签：创建 assign utf8 pen size tor 打印 padding 参数
本章接着NSObject头文件解析 / 消息机制 / Runtime解读(一)写
给类添加属性:
BOOL class_addProperty(Class cls, const char *name, const objc_property_attribute_t *attributes, unsigned int attributeCount)
其中有一个参数我们再在上一篇中提到过
typedef struct {
const char *name; /**< The name of the attribute */
const char *value; /**< The value of the attribute (usually empty) */
} objc_property_attribute_t;
我们看下常见的赋值
| 常用attribute | name | value |
| nonatomic | "N" | "" |
| strong/retain | "&" | "" |
| weak | "W" | "" |
| 属性的类型type | "T" | "@TypeName", eg"@\"NSString\"" |
| 属性对应的实例变量Ivar | "V" | "Ivar_name", eg "_name" |
| readonly | "R" | "" |
| getter | "G" | "GetterName", eg"isRight" |
| setter | "S" | "SetterName", eg"setName" |
| assign/atomic | 默认即为assign和retain |
例子:
- (void)viewDidLoad { [super viewDidLoad]; //创建一个对象 ClassA *aClass = [ClassA new]; //创建一个attributes objc_property_attribute_t nonatmoic = {"N", ""}; objc_property_attribute_t strong = {"&", ""}; objc_property_attribute_t type = {"T", "@\"NSString\""}; objc_property_attribute_t ivar = {"V", "_name"}; objc_property_attribute_t attributes[] = {nonatmoic, strong, type, ivar, getter, setter}; //给对象类添加属性 BOOL result = class_addProperty([aClass class], "name", attributes, 4); if (result) { NSLog(@"添加成功"); } else { NSLog(@"添加失败"); } //读取添加属性 objc_property_t property = class_getProperty([aClass class], "name"); //获取添加的属性的名称 NSString *propertyName = [NSString stringWithUTF8String:property_getName(property)]; //打印获取到的属性名 NSLog(@"获取到的属性名为: %@", propertyName); }
运行结果:
2017-02-03 15:52:01.949 RunTimeDemo[786:37263] 添加成功 2017-02-03 15:52:01.949 RunTimeDemo[786:37263] 获取到的属性名为: name
替换属性:
void class_replaceProperty(Class cls, const char *name, const objc_property_attribute_t *attributes, unsigned int attributeCount)
例子:
//创建一个对象 ClassA *aClass = [ClassA new]; //创建一个attributes objc_property_attribute_t nonatmoic = {"N", ""}; objc_property_attribute_t strong = {"&", ""}; objc_property_attribute_t type = {"T", "@\"NSString\""}; objc_property_attribute_t ivar = {"V", "_name"}; objc_property_attribute_t attributes[] = {nonatmoic, strong, type, ivar}; //替换属性 class_replaceProperty([aClass class], "name", attributes, 4);
运行时创建新类:
Class objc_allocateClassPair(Class superclass, const char *name, size_t extraBytes)
注册创建的新类:
void objc_registerClassPair(Class cls)
例子:
void printA(){ NSLog(@"Print A"); } - (void)viewDidLoad { [super viewDidLoad]; //创新新类 Class NewClass = objc_allocateClassPair([NSObject class], "NewObject", 0); //注册类 objc_registerClassPair(NewClass); //给类添加方法 class_addMethod([NewClass class], @selector(printA), (IMP)printA, "v@:"); //创建实例 id ob = [NewClass new]; //实例执行方法 [ob printA]; }
运行结果:
2017-02-03 18:11:34.091 RunTimeDemo[1114:96700] Print A
先Mark在这里, 后面会继续更新
NSObject头文件解析 / 消息机制 / Runtime解读 (二)
标签：创建 assign utf8 pen size tor 打印 padding 参数
原文地址：http://www.cnblogs.com/zhouxihi/p/6363103.html
