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runtime 常用方法实例

runtime 常用方法实例

作者: 圉湢 | 来源:发表于2019-05-13 18:59 被阅读0次

    Runtime（也就是运行时），它基本上是用C和汇编写的，这个库使得C语言有了面向对象的能力。所以习惯了面向对象编程的小伙们好像对于C的API一般都不太友好，但是又有很多C的API强大到别人问你你不知道那你都抬不起头，Runtime就是其中之一。关于它的传说有很多，可以说在有的人手里牛逼的不可一世。下面我们主要看一下runtime基本使用的方法:

    1、获取当前类变量列表

    不啰嗦直接上代码：

      获取当前类 的所以变量
  unsigned int outCount;
    Ivar *ivars = class_copyIvarList([PeopleModel class], &outCount);
    SGTLog(@"\n\n\nPeopleModel类包含 变量数量：%u", outCount);
    
    for (int i = 0; i < outCount; i++) {
        Ivar ivar = ivars[i];
        const char *ivarName = ivar_getName(ivar);
        const char *ivarType = ivar_getTypeEncoding(ivar);
        SGTLog(@"PeopleModel类包含 变量名为：%s 变量类型为：%s", ivarName, ivarType);
    }
    //由于ARC只适用于Foundation等框架，对runtime 等并不适用，所以ivars需要free()手动释放。
    free(ivars);
    
    获取当前类 实例对象的所以变量
    unsigned int count_p;
    Ivar *ivars_p = class_copyIvarList([self.people class], &count_p);
    SGTLog(@"\n\n\nself.people实例包含 变量数量：%u", count_p);
    
    for (int i = 0; i < count_p; i++) {
        Ivar ivar_p = ivars_p[i];
        const char *ivarName_p = ivar_getName(ivar_p);
        const char *ivarType_p = ivar_getTypeEncoding(ivar_p);
        SGTLog(@"self.people实例包含 变量名为：%s 变量类型为：%s", ivarName_p, ivarType_p);
    }
    
    free(ivars_p);

    打印结果

    PeopleModel类包含 变量数量：7
2019-05-13 14:31:33.967546+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:78]
PeopleModel类包含 变量名为：_weight 变量类型为：f
2019-05-13 14:31:33.967704+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:78]
PeopleModel类包含 变量名为：_sex 变量类型为：B
2019-05-13 14:31:33.967838+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:78]
PeopleModel类包含 变量名为：_height 变量类型为：f
2019-05-13 14:31:33.967978+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:78]
PeopleModel类包含 变量名为：_age 变量类型为：q
2019-05-13 14:31:33.968102+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:78]
PeopleModel类包含 变量名为：_province 变量类型为：@"NSString"
2019-05-13 14:31:33.968225+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:78]
PeopleModel类包含 变量名为：_city 变量类型为：@"NSString"
2019-05-13 14:31:33.968349+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:78]
PeopleModel类包含 变量名为：_county 变量类型为：@"NSString"
2019-05-13 14:31:33.968561+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:85]


self.people实例包含 变量数量：7
2019-05-13 14:31:33.969885+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:91]
self.people实例包含 变量名为：_weight 变量类型为：f
2019-05-13 14:31:33.970044+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:91]
self.people实例包含 变量名为：_sex 变量类型为：B
2019-05-13 14:31:33.970163+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:91]
self.people实例包含 变量名为：_height 变量类型为：f
2019-05-13 14:31:33.970283+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:91]
self.people实例包含 变量名为：_age 变量类型为：q
2019-05-13 14:31:33.970397+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:91]
self.people实例包含 变量名为：_province 变量类型为：@"NSString"
2019-05-13 14:31:33.970513+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:91]
self.people实例包含 变量名为：_city 变量类型为：@"NSString"
2019-05-13 14:31:33.970630+0800 RuntimeDemo[19130:320593] 
-[ViewController testIvar] [ViewController.m  Line:91]
self.people实例包含 变量名为：_county 变量类型为：@"NSString"
    2、获取当前类属性列表

    代码如下：

     unsigned int outPropertyCount;
    objc_property_t *propertys = class_copyPropertyList([PeopleModel class],&outPropertyCount);
    SGTLog(@"\n\n\nPeopleModel类包含 属性数量：%u", outPropertyCount);
    for (int i = 0; i < outPropertyCount; i++) {
        objc_property_t property = propertys[i];
        const char *propertyName = property_getName(property);
        const char *propertyAttributes = property_getAttributes(property);
        SGTLog(@"nPeopleModel类包含 属性名为：%s 变量属性为：%s", propertyName, propertyAttributes);
    }
    free(propertys);

    打印结果，People类共有8个属性

    PeopleModel类包含 属性数量：8
2019-05-13 14:52:17.738854+0800 RuntimeDemo[19435:328966] 
-[ViewController testProperty] [ViewController.m  Line:109]
nPeopleModel类包含 属性名为：fatherName 变量属性为：T@"NSString",C,D,N
2019-05-13 14:52:17.739009+0800 RuntimeDemo[19435:328966] 
-[ViewController testProperty] [ViewController.m  Line:109]
nPeopleModel类包含 属性名为：motherName 变量属性为：T@"NSString",C,D,N
2019-05-13 14:52:17.739128+0800 RuntimeDemo[19435:328966] 
-[ViewController testProperty] [ViewController.m  Line:109]
nPeopleModel类包含 属性名为：age 变量属性为：Tq,N,V_age
2019-05-13 14:52:17.739276+0800 RuntimeDemo[19435:328966] 
-[ViewController testProperty] [ViewController.m  Line:109]
nPeopleModel类包含 属性名为：sex 变量属性为：TB,N,V_sex
2019-05-13 14:52:17.739404+0800 RuntimeDemo[19435:328966] 
-[ViewController testProperty] [ViewController.m  Line:109]
nPeopleModel类包含 属性名为：height 变量属性为：Tf,N,V_height
2019-05-13 14:52:17.739541+0800 RuntimeDemo[19435:328966] 
-[ViewController testProperty] [ViewController.m  Line:109]
nPeopleModel类包含 属性名为：province 变量属性为：T@"NSString",C,N,V_province
2019-05-13 14:52:17.739697+0800 RuntimeDemo[19435:328966] 
-[ViewController testProperty] [ViewController.m  Line:109]
nPeopleModel类包含 属性名为：city 变量属性为：T@"NSString",C,N,V_city
2019-05-13 14:52:17.739849+0800 RuntimeDemo[19435:328966] 
-[ViewController testProperty] [ViewController.m  Line:109]
nPeopleModel类包含 属性名为：county 变量属性为：T@"NSString",C,N,V_county
2019-05-13 14:52:17.740080+0800 RuntimeDemo[19435:328966] 
-[ViewController testProperty] [ViewController.m  Line:116]
    3、获取当前类方法列表

    代码如下：

     unsigned int outMethodCount;
    Method *methods = class_copyMethodList([PeopleModel class], &outMethodCount);
    SGTLog(@"\n\n\nPeopleModel类包含 方法数量：%u", outMethodCount);
    for (int i = 0; i < outMethodCount; i++) {
        Method method = methods[i];
        SEL method_name = method_getName(method);//方法名
        const char * method_types  = method_getTypeEncoding(method);//方法类型编码
        IMP method_imp = method_getImplementation(method);//方法实现
        unsigned int ArgumentsNum  =  method_getNumberOfArguments(method);//参数个数
        SGTLog(@"PeopleModel类包含 方法 名称为：%@ 方法类型为：%s  method_imp %p 参数个数: %d ",NSStringFromSelector(method_name), method_types,&method_imp,ArgumentsNum);
    }
    free(methods);

    打印结果显示，People共有方法22个包含属性的setter getter 方法，也包含分类中的方法

    PeopleModel类包含 方法数量：22
2019-05-13 17:30:45.841292+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：fatherName 方法类型为：@16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.841507+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：motherName 方法类型为：@16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.841651+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：isEat 方法类型为：B16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.841807+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：isEat 方法类型为：B16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.841945+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：isWork 方法类型为：B16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.842094+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：setFatherName: 方法类型为：v24@0:8@16  method_imp 0x7ffeea98c7f8 参数个数: 3
2019-05-13 17:30:45.842221+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：setMotherName: 方法类型为：v24@0:8@16  method_imp 0x7ffeea98c7f8 参数个数: 3
2019-05-13 17:30:45.853483+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：isHeight: 方法类型为：B24@0:8@16  method_imp 0x7ffeea98c7f8 参数个数: 3
2019-05-13 17:30:45.853635+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：sex 方法类型为：B16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.853767+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：setSex: 方法类型为：v20@0:8B16  method_imp 0x7ffeea98c7f8 参数个数: 3
2019-05-13 17:30:45.853892+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：province 方法类型为：@16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.854019+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：setProvince: 方法类型为：v24@0:8@16  method_imp 0x7ffeea98c7f8 参数个数: 3
2019-05-13 17:30:45.854145+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：county 方法类型为：@16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.854278+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：setCounty: 方法类型为：v24@0:8@16  method_imp 0x7ffeea98c7f8 参数个数: 3
2019-05-13 17:30:45.854402+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：.cxx_destruct 方法类型为：v16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.854522+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：dealloc 方法类型为：v16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.854748+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：height 方法类型为：f16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.855102+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：setHeight: 方法类型为：v20@0:8f16  method_imp 0x7ffeea98c7f8 参数个数: 3
2019-05-13 17:30:45.855471+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：setAge: 方法类型为：v24@0:8q16  method_imp 0x7ffeea98c7f8 参数个数: 3
2019-05-13 17:30:45.855768+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：age 方法类型为：q16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.856054+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：setCity: 方法类型为：v24@0:8@16  method_imp 0x7ffeea98c7f8 参数个数: 3
2019-05-13 17:30:45.856447+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:137]
PeopleModel类包含 方法 名称为：city 方法类型为：@16@0:8  method_imp 0x7ffeea98c7f8 参数个数: 2
2019-05-13 17:30:45.856783+0800 RuntimeDemo[25078:406610] 
-[ViewController testMethod] [ViewController.m  Line:146]
    4、替换当前类实例方法的实现（类方法同样）

    一样，不啰嗦直接上代码

     /// 替换方法实现
    SEL originalSelector = @selector(isEat);
    SEL swizzledSelector = @selector(isWork);
    
//    Method originalMethod = class_getInstanceMethod([PeopleModel class], originalSelector);
//    Method swizzledMethod = class_getInstanceMethod([PeopleModel class], swizzledSelector);
   
    //self.people 类型已被赋值为Model
    Method originalMethod = class_getInstanceMethod([self.people class], originalSelector);
    Method swizzledMethod = class_getInstanceMethod([self.people class], swizzledSelector);
//    if (swizzledMethod == nil) {
//        return;
//    }
    
    //1、交换两个方法的实现
    method_exchangeImplementations(originalMethod, swizzledMethod);
    
//    IMP    originalIMP    = method_getImplementation(originalMethod);
//    IMP    swizzledIMP    = method_getImplementation(swizzledMethod);
//    //2、用swizzledMethod的实现取代originalMethod的实现
//    class_replaceMethod([self.people class], originalSelector, swizzledIMP, method_getTypeEncoding(swizzledMethod));
//
//    //3、把swizzledVCMethod方法的实现赋值给originalMethod
//    method_setImplementation(originalMethod,swizzledIMP);
 
    //调用方法测试 //如果前边调用了[self textClass]方法 self.people 类型已被赋值为Model ，相当于调用Model 实例的isEat方法，Model 未实现isEat方法，Model类作了消息截取，可以调用成功
    [self.people isEat];

    替换方法的实现有三种方法

    1、交换两个方法的实现
    method_exchangeImplementations(originalMethod,swizzledMethod);

    2、用swizzledMethod的实现取代originalMethod的实现
    class_replaceMethod([self.people class], originalSelector,method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod));

    3、把swizzledVCMethod方法的实现赋值给originalMethod
    method_setImplementation(originalMethod,method_getImplementation(swizzledMethod));

    这三种方法都可以在调用originalMethod 的时候替换为swizzledMethod的实现

    我们在项目中调用没有实现的方法会崩溃，怎么避免呢？我们可以通过消息转发来实现，代码如下，
    并且重写消息转发的方法：
    方法一：

    //Model.m 文件中创建
-(void)noObjMethod{
    NSLog(@"未实现这个实例方法");
}
+(void)noClassMethod{
    NSLog(@"未实现这个类方法");
}
//并且重写消息转发的方法：
// 当一个对象调用未实现的方法，会调用这个方法处理,并且会把对应的方法列表传过来.
//注意:实例方法是存在于当前对象对应的类的方法列表中
+(BOOL)resolveInstanceMethod:(SEL)sel{
    SEL aSel = NSSelectorFromString(@"noObjMethod");
    Method aMethod = class_getInstanceMethod(self, aSel);
    BOOL addMethod = class_addMethod(self, sel, method_getImplementation(aMethod), "v@:");
    return addMethod;
}
// 当一个类调用未实现的方法，会调用这个方法处理,并且会把对应的方法列表传过来.
//注意:类方法是存在于类的元类的方法列表中
+(BOOL)resolveClassMethod:(SEL)sel{
    SEL aSel = NSSelectorFromString(@"noClassMethod");
    Method aMethod = class_getClassMethod(self, aSel);
    BOOL addMethod =  class_addMethod(object_getClass(self), sel, method_getImplementation(aMethod), "v@:");
    return addMethod;
}

    打印结果

    2019-05-13 18:31:46.605919+0800 RuntimeDemo[28185:448815] 未实现这个实例方法

    方法二：

    //消息转发
-(id)forwardingTargetForSelector:(SEL)aSelector{
    //获取people类
    Class peopleClass = NSClassFromString(@"PeopleModel");
    
    if (class_respondsToSelector(peopleClass, aSelector)) {
        return [[peopleClass alloc]init];
    }
    return self;
}

    打印结果

    2019-05-13 18:35:25.711990+0800 RuntimeDemo[28222:449877] 
-[PeopleModel(Family) isEat] [PeopleModel+Family.m  Line:22]
 (null) 没有吃饭

    方法三：

    - (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector {
    if ([NSStringFromSelector(aSelector) isEqualToString:@"isEat"]) {
        return [NSMethodSignature signatureWithObjCTypes:"v@:"];
    }
    return [super methodSignatureForSelector:aSelector];
}
-(void)forwardInvocation:(NSInvocation *)anInvocation{
    [anInvocation invokeWithTarget:[[NSClassFromString(@"PeopleModel") alloc] init]];
}

    打印结果

    2019-05-13 18:40:26.972046+0800 RuntimeDemo[28102:446152] 
-[PeopleModel(Family) isEat] [PeopleModel+Family.m  Line:22]
 (null) 没有吃饭

    以上三种方法都可以实现消息转发，在调用isEat时进行处理，不会引起崩溃。

    Runtime使用实例就先到这里了。
    测试Demo地址直通车

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