iOS Objc Runtime 教程+实例Demo.docx

1、iOS Objc Runtime 教程+实例DemoiOS Objc Runtime 教程+实例Demo应用场景将某些OC代码转为运行时代码，探究底层，比如block的实现原理拦截系统自带的方法调用（Swizzle 黑魔法），比如拦截imageNamed:、viewDidLoad、alloc实现分类也可以增加属性实现NSCoding的自动归档和自动解档实现字典和模型的自动转换。(MJExtension)修BUG神器，如果大型框架的BUG 通过Runtime来解决，非常好用。一些常用类型MethodMethod An opaque type that represents a method in

2、 a class definition. Declaration typedef struct objc_method *Method;代表类定义中的方法的不透明类型。ClassClass An opaque type that represents an Objective-C class. Declaration typedef struct objc_class *Class;代表Objective-C中的类IvarAn opaque type that represents an instance variable. Declaration typedef struct objc_iv

3、ar *Ivar;代表实例变量IMPIMP A pointer to the start of a method implementation.指向方法实现的开始的内存地址的指针。SELSEL Defines an opaque type that represents a method selector. Declaration typedef struct objc_selector *SEL;代表方法的选择器类与对象操作函数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

4、 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 classBOOL 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_getInstanceVa

5、riable ( 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, u

6、nsigned 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

7、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

8、 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 );

9、IMP class_getMethodImplementation_stret ( Class cls, SEL name );/ 类实例是否响应指定的selectorBOOL 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

10、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 );实例/-/ MyClass.hinterface MyClass : NSObject property (nonatomic, strong) NSArray *array;property (nonatomic, copy)

11、NSString *string;- (void)method1;- (void)method2;+ (void)classMethod1;end/-/ MyClass.m#import MyClass.hinterface MyClass () NSInteger _instance1;NSString * _instance2;property (nonatomic, assign) NSUInteger integer;- (void)method3WithArg1:(NSInteger)arg1 arg2:(NSString *)arg2;endimplementation MyCla

12、ss+ (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 MyCl

13、ass *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) ? : no

14、t); NSLog(=); Class meta_class = objc_getMetaClass(class_getName(cls); NSLog(%ss 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

15、; i outCount; i+) Ivar ivar = ivarsi; NSLog(instance variables 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

16、_copyPropertyList(cls, &outCount); for (int i = 0; i outCount; i+) objc_property_t property = propertiesi; NSLog(propertys name: %s, property_getName(property); free(properties); objc_property_t array = class_getProperty(cls, array); if (array != NULL) NSLog(property %s, property_getName(array); NSL

17、og(=); / 方法操作 Method *methods = class_copyMethodList(cls, &outCount); for (int i = 0; i outCount; i+) Method method = methodsi; NSLog(methods signature: %s, method_getName(method); free(methods); Method method1 = class_getInstanceMethod(cls, selector(method1); if (method1 != NULL) NSLog(method %s, m

18、ethod_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:) ?

19、 : 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 = protocolsi; NSLog(protocol name: %s, protocol_getName(pro

20、tocol); NSLog(MyClass is% responsed to protocol %s, class_conformsToProtocol(cls, protocol) ? : not, protocol_getName(protocol); NSLog(=); return 0;动态创建类和对象动态创建类/ 创建一个新类和元类Class objc_allocateClassPair ( Class superclass, const char *name, size_t extraBytes ); /如果创建的是root class，则superclass为Nil。extraB

21、ytes通常为0/ 销毁一个类及其相关联的类void objc_disposeClassPair ( Class cls ); /在运行中还存在或存在子类实例，就不能够调用这个。/ 在应用中注册由objc_allocateClassPair创建的类void objc_registerClassPair ( Class cls ); /创建了新类后，然后使用class_addMethod，class_addIvar函数为新类添加方法，实例变量和属性后再调用这个来注册类，再之后就能够用了。使用实例Class cls = objc_allocateClassPair(MyClass.class, M

22、ySubClass, 0);class_addMethod(cls, selector(submethod1), (IMP)imp_submethod1, v:);class_replaceMethod(cls, selector(method1), (IMP)imp_submethod1, v:);class_addIvar(cls, _ivar1, sizeof(NSString *), log(sizeof(NSString *), i);objc_property_attribute_t type = T, NSString;objc_property_attribute_t owne

23、rship = C, ;objc_property_attribute_t backingivar = V, _ivar1;objc_property_attribute_t attrs = type, ownership, backingivar;class_addProperty(cls, property2, attrs, 3);objc_registerClassPair(cls);id instance = cls alloc init;instance performSelector:selector(submethod1);instance performSelector:sel

24、ector(method1);动态创建对象/ 创建类实例id class_createInstance ( Class cls, size_t extraBytes ); /会在heap里给类分配内存。这个方法和+alloc方法类似。/ 在指定位置创建类实例id objc_constructInstance ( Class cls, void *bytes );/ 销毁类实例void * objc_destructInstance ( id obj ); /不会释放移除任何相关引用测试下效果/可以看出class_createInstance和alloc的不同id theObject = cla

25、ss_createInstance(NSString.class, sizeof(unsigned);id str1 = theObject init;NSLog(%, str1 class);id str2 = NSString alloc initWithString:test;NSLog(%, str2 class);实例操作函数这些函数是针对创建的实例对象的一系列操作函数。整个对象操作的函数/ 返回指定对象的一份拷贝id object_copy ( id obj, size_t size );/ 释放指定对象占用的内存id object_dispose ( id obj );应用场景/

26、把a转换成占用更多空间的子类bNSObject *a = NSObject alloc init;id newB = object_copy(a, class_getInstanceSize(MyClass.class);object_setClass(newB, MyClass.class);object_dispose(a);对象实例变量进行操作的函数/ 修改类实例的实例变量的值Ivar object_setInstanceVariable ( id obj, const char *name, void *value );/ 获取对象实例变量的值Ivar object_getInstan

27、ceVariable ( id obj, const char *name, void *outValue );/ 返回指向给定对象分配的任何额外字节的指针void * object_getIndexedIvars ( id obj );/ 返回对象中实例变量的值id object_getIvar ( id obj, Ivar ivar );/ 设置对象中实例变量的值void object_setIvar ( id obj, Ivar ivar, id value );对对象类操作/ 返回给定对象的类名const char * object_getClassName ( id obj );/ 返回对象的类Class object_getClass ( id obj );/ 设置对象的类Class object_setClass ( id obj, Class cls );获取类定义/ 获取已注册的类定义的列表int objc_getClassList ( Class *buffer, int bufferCount );/ 创建并返回一个指向所有已注册类的指针列表Class * objc_copyClassList ( unsigned int