原文来自:Runtime方法的使用—Class篇
感谢:xietao3
方法交换:
+ (void)load{
//方法交换应该被保证，在程序中只会执行一次
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
//获得viewController的生命周期方法的selector
SEL systemSel = @selector(viewWillAppear:);
//自己实现的将要被交换的方法的selector
SEL swizzSel = @selector(swiz_viewWillAppear:);
//两个方法的Method
Method systemMethod = class_getInstanceMethod([self class], systemSel);
Method swizzMethod = class_getInstanceMethod([self class], swizzSel);
//首先动态添加方法，实现是被交换的方法，返回值表示添加成功还是失败
BOOL isAdd = class_addMethod(self, systemSel, method_getImplementation(swizzMethod), method_getTypeEncoding(swizzMethod));
if (isAdd) {
//如果成功，说明类中不存在这个方法的实现
//将被交换方法的实现替换到这个并不存在的实现
class_replaceMethod(self, swizzSel, method_getImplementation(systemMethod), method_getTypeEncoding(systemMethod));
}else{
//否则，交换两个方法的实现
method_exchangeImplementations(systemMethod, swizzMethod);
}
});
}
- (void)swiz_viewWillAppear:(BOOL)animated{
//这时候调用自己，看起来像是死循环
//但是其实自己的实现已经被替换了
[self swiz_viewWillAppear:animated];// 如果不调用,则原方法的实现将被屏蔽
NSLog(@"hello");
}
常用方法
- (void)viewDidLoad {
[super viewDidLoad];
// 调用方法方案1
// objc_msgSend(self,@selector(initial:),@"完成初始化");
// 调用方法方案2
Method method = [self class_getInstanceMethod:SelfClass selector:@selector(initial:)];
[self method_invoke:self method:method];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark - Initialize
- (void)initial:(NSString *)str{
if (str) NSLog(@"%@",str);
_person = [[Person alloc] init];
_person.name = @"xietao";
_person.age = @"18";
_person.gender = @"male";
_person.city = @"shanghai";
[self logRunTimeAction:nil];
}
#pragma mark - IBAction
- (IBAction)logRunTimeAction:(id)sender {
objc_property_attribute_t attrs[] = { { "T", "@\"NSString\"" }, { "&", "N" }, { "V", "" } };
size_t objSize = class_getInstanceSize([_person class]);
size_t allocSize = 2 * objSize;
uintptr_t ptr = (uintptr_t)calloc(allocSize, 1);
// Class
[self class_getClassName:SelfClass];
[self class_getSuperClass:SelfClass];
[self class_getInstanceSize:SelfClass];
[self class_getInstanceVariable:SelfClass name:"_person"];
[self class_getClassVariable:SelfClass name:"Person"];
[self class_getInstanceMethod:SelfClass selector:@selector(class_getInstanceMethod:selector:)];
[self.class class_getClassMethod:SelfClass selector:@selector(class_getClassMethod:selector:)];
[self class_getProperty:SelfClass name:"person"];
[self class_getMethodImplementation:SelfClass selector:@selector(class_getMethodImplementation:selector:)];
[self class_getMethodImplementation_stret:SelfClass selector:@selector(class_getMethodImplementation_stret:selector:)];
[self class_copyIvarList:[_person class]];
[self class_copyPropertyList:[_person class]];
[self class_copyMethodList:[_person class]];
[self class_copyProtocolList:[_person class]];
[self class_addIvar:[_person class] name:"country" size:sizeof(NSString *) alignment:0 types:"@"]; // 无效方法
[self class_addProperty:[_person class] name:"country" attributes:nil attributeCount:3];
[self class_addMethod:SelfClass selector:NSSelectorFromString(@"runtimeTestMethod:") imp:nil types:"v@:@"];
[self class_addProtocol:[_person class] protocol:@protocol(RuntimeBaseProtocol)];
[self class_replaceProperty:[_person class] name:"country" attributes:nil attributeCount:3];
[self class_replaceMethod:[_person class] selector:@selector(runtimeTestAction1) imp:class_getMethodImplementation([_person class], @selector(runtimeTestAction2)) types:"v@:"];
[self class_respondsToSelector:[_person class] selector:@selector(runtimeTestAction1)];
[self class_isMetaClass:object_getClass(self.superclass)];
[self class_conformsToProtocol:[_person class] protocol:NSProtocolFromString(@"RuntimeBaseProtocol")];
[self class_createInstance:[_person class] extraBytes:class_getInstanceSize([_person class])];
}
#pragma mark - Class 创建
- (void)class_createInstance:(Class)class extraBytes:(size_t)extraBytes {
Person *tempPerson = class_createInstance(class, extraBytes);
tempPerson.name = @"instance creat Success";
NSLog(@"%s%@",__func__,tempPerson.name);
}
#pragma mark - Class 类名，父类，元类；实例变量，成员变量；属性；实例方法，类方法，方法实现；
/**
* 获取类的类名
*
* @param class 类
*/
- (void)class_getClassName:(Class)class {
NSLog(@"%s:%s",__func__,class_getName(class));
}
/**
* 获取类的父类
*
* @param class 类
*/
- (void)class_getSuperClass:(Class)class {
NSLog(@"%s%@",__func__,NSStringFromClass(class_getSuperclass(class)));
}
/**
* 获取实例大小
*
* @param class 类
*/
- (void)class_getInstanceSize:(Class)class {
NSLog(@"%s%zu",__func__,class_getInstanceSize(class));
}
/**
* 获取类中指定名称实例成员变量的信息
*
* @param class 类
* @param name 成员变量名
*/
- (void)class_getInstanceVariable:(Class)class name:(const char *)name {
Ivar ivar = class_getInstanceVariable(class,name);
NSLog(@"%s%s%s",__func__,[self ivar_getTypeEncoding:ivar],[self ivar_getName:ivar]);
}
/**
* 获取类成员变量的信息（该函数没有作用，官方解释:http://lists.apple.com/archives/objc-language/2008/Feb/msg00021.html
*
* @param class 类
* @param name 成员变量名
*/
- (void)class_getClassVariable:(Class)class name:(const char *)name {
Ivar ivar = class_getClassVariable(class,name);
NSLog(@"%s%s%s",__func__,[self ivar_getTypeEncoding:ivar],[self ivar_getName:ivar]);
}
/**
* 获取属性的信息(与获取成员变量信息类似，不同的是不用打_)
*
* @param class 类
* @param name 属性名
*/
- (void)class_getProperty:(Class)class name:(const char *)name {
objc_property_t property = class_getProperty(class,name);
NSLog(@"%s%s%s",__func__,[self property_getName:property] ,[self property_getAttributes:property]);
[self property_copyAttributeList:property];
}
/**
* 获取类制定方法的信息
*
* @param class 类
* @param selector 方法
*/
- (Method)class_getInstanceMethod:(Class)class selector:(SEL)selector {
Method method = class_getInstanceMethod(class, selector);
NSLog(@"%s%s%u",__func__,sel_getName(method_getName(method)) ,[self method_getNumberOfArguments:method]);
return method;
}
/**
* 获取类方法的信息
*
* @param class 类
* @param selector 方法
*/
+ (Method)class_getClassMethod:(Class)class selector:(SEL)selector {
Method method = class_getClassMethod(class, selector);
NSLog(@"%s%s%u",__func__,sel_getName(method_getName(method)) ,method_getNumberOfArguments(method));
return method;
}
/**
* 获取方法具体实现
*
* @param class 类
* @param selector 方法
*
* @return IMP
*/
- (IMP)class_getMethodImplementation:(Class)class selector:(SEL)selector {
IMP imp = class_getMethodImplementation(class, selector);
return imp;
}
/**
* 获取类中的方法的实现,该方法的返回值类型为struct
*
* @param class 类
* @param selector 方法
*
* @return IMP
*/
- (IMP)class_getMethodImplementation_stret:(Class)class selector:(SEL)selector {
IMP imp = class_getMethodImplementation_stret(class, selector);
return imp;
}
#pragma mark - Class 成员变量列表；属性列表；方法列表；协议列表；
/**
* 获取成员变量列表
*
* @param class 类
*/
- (void)class_copyIvarList:(Class)class {
unsigned int count;
Ivar *ivarList = class_copyIvarList(class, &count);
NSLog(@"%s",__func__);
for (int i = 0; i < count; i++) {
Ivar ivar = ivarList[i];
// 获取成员属性名
NSString *name = [NSString stringWithUTF8String:[self ivar_getName:ivar]];
NSString *type = [NSString stringWithUTF8String:[self ivar_getTypeEncoding:ivar]];
// NSString *value = object_getIvar(obj, ivar);
NSLog(@"%@%@",type,name);
}
}
- (void)class_copyPropertyList:(Class)class {
unsigned int count;
objc_property_t *propertyList = class_copyPropertyList(class,&count);
NSLog(@"%s",__func__);
for (int i = 0; i < count; i++) {
objc_property_t property = propertyList[i];
// 获取成员属性名
NSString *name = [NSString stringWithUTF8String:[self property_getName:property]];
NSString *type = [NSString stringWithUTF8String:[self property_getAttributes:property]];
NSLog(@"%@%@",type,name);
}
}
/**
* 获取方法列表
*
* @param class 类
*/
- (void)class_copyMethodList:(Class)class {
unsigned int count;
Method *methodList = class_copyMethodList(class,&count);
for (int i = 0; i < count; i++) {
Method method = methodList[i];
NSLog(@"%s%s",__func__,sel_getName(method_getName(method)));
}
}
/**
* 获取协议列表
*
* @param class 类
*/
- (void)class_copyProtocolList:(Class)class {
unsigned int count;
Protocol **protocolList = class_copyProtocolList(class,&count);
for (int i = 0; i < count; i++) {
Protocol *protocol = protocolList[i];
NSLog(@"%s%s",__func__,[self protocol_getName:protocol]);
}
}
#pragma mark - Class add: 成员变量；属性；方法；协议
/**
* 添加成员变量(添加成员变量只能在运行时创建的类，且不能为元类)
*
* @param class 类
* @param name 成员变量名字
* @param size 大小
* @param alignment 对其方式
* @param types 参数类型
*/
- (void)class_addIvar:(Class)class name:(const char *)name size:(size_t)size alignment:(uint8_t)alignment types:(const char *)types {
// if (class_addIvar([_person class], "country", sizeof(NSString *), 0, "@")) {
if (class_addIvar(class, name, size, alignment, types)) {
NSLog(@"%sadd ivar success",__func__);
}else{
NSLog(@"%sadd ivar fail",__func__);
}
}
/**
* 添加属性
*
* @param class 类
* @param name 属性名
* @param attributes 参数
* @param attributeCount 参数数量
*/
- (void)class_addProperty:(Class)class name:(const char *)name attributes:(const objc_property_attribute_t *)attributes attributeCount:(unsigned int)attributeCount {
objc_property_attribute_t type = { "T", "@\"NSString\"" };
objc_property_attribute_t ownership = { "&", "N" }; // C = copy
objc_property_attribute_t backingivar = { "V", "" };
objc_property_attribute_t attrs[] = { type, ownership, backingivar };
if (class_addProperty(class, name, attrs, attributeCount)) {
NSLog(@"%sadd Property success",__func__);
}else{
NSLog(@"%sadd Property fail",__func__);
}
// [self class_copyPropertyList:class];
}
/**
* 添加方法
*
* @param class 类
* @param selector 方法
* @param imp 方法实现
* @param types 类型
*/
- (void)class_addMethod:(Class)class selector:(SEL)selector imp:(IMP)imp types:(const char *)types {
if (class_addMethod(class,selector,class_getMethodImplementation(class, selector),types)) {
NSLog(@"%sadd method success",__func__);
}else{
NSLog(@"%sadd method fail",__func__);
}
// [self class_copyMethodList:class];
}
/**
* 添加协议
*
* @param class 类
* @param protocol 协议
*/
- (void)class_addProtocol:(Class)class protocol:(Protocol *)protocol {
if (class_addProtocol(class, protocol)) {
NSLog(@"%sadd protocol success",__func__);
}else{
NSLog(@"%sadd protocol fail",__func__);
}
// [self class_copyProtocolList:class];
}
#pragma marl - Class replace：属性；方法
/**
* 替换属性的信息(如果没有原属性会新建一个属性)
*
* @param class 类
* @param name 属性名
* @param attributes 类型
* @param attributeCount 类型数量
*/
- (void)class_replaceProperty:(Class)class name:(const char *)name attributes:(const objc_property_attribute_t *)attributes attributeCount:(unsigned int)attributeCount {
objc_property_attribute_t type = { "T", "@\"NSString\"" };
objc_property_attribute_t ownership = { "C", "" }; // C = copy
objc_property_attribute_t backingivar = { "V", "" };
objc_property_attribute_t attrs[] = { type, ownership, backingivar };
class_replaceProperty(class, name, attrs, 3);
// [self class_copyPropertyList:class];
}
/**
* 替代方法的实现
*
* @param class 类
* @param selector 被替代的方法
* @param imp 替代方法
* @param types 类型
*/
- (void)class_replaceMethod:(Class)class selector:(SEL)selector imp:(IMP)imp types:(const char *)types {
class_replaceMethod(class, selector, imp, types);
NSLog(@"%s",__func__);
[_person runtimeTestAction1];
}
#pragma mark - Class 判断
/**
* 查看类是否相应指定方法
*
* @param class 类
* @param selector 方法
*/
- (void)class_respondsToSelector:(Class)class selector:(SEL)selector {
if (class_respondsToSelector(class,selector)) {
NSLog(@"%s %@ exist",__func__,NSStringFromClass(class));
}else{
NSLog(@"%s %@ non-exist",__func__,NSStringFromClass(class));
}
}
/**
* 查看类是否为元类
*
* @param class 类
*/
- (void)class_isMetaClass:(Class)class {
if (class_isMetaClass(class)) {
NSLog(@"%s %@ isMetaClass",__func__,NSStringFromClass(class));
}else{
NSLog(@"%s %@ non-isMetaClass",__func__,NSStringFromClass(class));
}
}
/**
* 查看类是否遵循指定协议
*
* @param class 类
* @param protocol 协议
*/
- (BOOL)class_conformsToProtocol:(Class)class protocol:(Protocol *)protocol {
if (class_conformsToProtocol(class, protocol)) {
NSLog(@"%s %@ conformsToProtocol %@",__func__,NSStringFromClass(class),NSStringFromProtocol(protocol));
return YES;
}else{
NSLog(@"%s %@ non-conformsToProtocol %@",__func__,NSStringFromClass(class),NSStringFromProtocol(protocol));
return NO;
}
}
