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Runtime的介绍与简单运用(一)

2019-11-09 18:32:46
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runtime简称运行时

        我们都知道Object-C是一种是根据C语言所衍生出来的语言,因此我们的代码在程序运行过程中都会被转化成C代码执行,而runtime就相当于这个桥梁,对于一个想要真正理解OC语言的人,学习runtime是必不可少的,好比想要深刻理解java,映射是必不可少一样。

例如[objc logMyInfo];会被转化成objc_msgSend(objc, @selector(logMyInfo));。

OC中一切都被设计成了对象,我们都知道一个类被初始化成一个实例,这个实例是一个对象。实际上一个类本质上也是一个对象,在runtime中用结构体表示。

例如导入#import <objc/runtime.h>我们可以从runtime中看到

/// An opaque type that rePResents a method in a class definition.描述类中的一个方法typedef struct objc_method *Method;/// An opaque type that represents an instance variable.实例变量typedef struct objc_ivar *Ivar;/// An opaque type that represents a category. 类别Categorytypedef struct objc_category *Category;/// An opaque type that represents an Objective-C declared property.类中声明的属性typedef struct objc_property *objc_property_t;//类在runtime中的表示struct objc_class {    Class isa  OBJC_ISA_AVAILABILITY;    //指针,顾名思义,表示是一个什么,    //实例的isa指向类对象,类对象的isa指向元类#if !__OBJC2__    //父类    Class super_class                                        OBJC2_UNAVAILABLE;    //类名    const char *name                                         OBJC2_UNAVAILABLE;    long version                                             OBJC2_UNAVAILABLE;    long info                                                OBJC2_UNAVAILABLE;    long instance_size                                       OBJC2_UNAVAILABLE;    //成员变量列表    struct objc_ivar_list *ivars                             OBJC2_UNAVAILABLE;    //方法列表    struct objc_method_list **methodLists                    OBJC2_UNAVAILABLE;    //缓存  一种优化,调用过的方法存入缓存列表,下次调用先找缓存    struct objc_cache *cache                                 OBJC2_UNAVAILABLE;    //协议列表    struct objc_protocol_list *protocols                     OBJC2_UNAVAILABLE;#endif    } OBJC2_UNAVAILABLE;

实战应用,获取类属性列表

1、首先我们先新建一个工程,然后创建一个测试类文件TestClass.h

2、然后新建一些测试类属性,代码如下

h文件

#import <Foundation/Foundation.h>@protocol TestDelegate <NSObject>- (void)testDelegateMethod;@end@interface TestClass : NSObject@property (nonatomic,weak) id<TestDelegate> delegate;@property (nonatomic,strong) NSString *outPrOne;- (void)thisTestMethod;@end/** 测试代理 */@protocol TestDelegateTwo <NSObject>- (void)testDelegateMethodTwo;@end@interface TestClassTwo : NSObject@property (nonatomic,weak) id<TestDelegateTwo> delegateTwo;- (void)thisTestMethodTwo;@endm文件
#import "TestClass.h"@interface TestClass ()<TestDelegateTwo>@end@implementation TestClass{    NSString *instanceOne;    TestClassTwo *testTwo;}- (instancetype)init{    self = [super init];    if (self) {        testTwo.delegateTwo = self;    }    return self;}- (void)thisTestMethod{    if ([self.delegate respondsToSelector:@selector(testDelegateMethod)]) {        [self.delegate testDelegateMethod];    }    [testTwo thisTestMethodTwo];}- (void)testDelegateMethodTwo{    NSLog(@"thisTestMethodTwo");}@end@implementation TestClassTwo- (void)thisTestMethodTwo{    if ([self.delegateTwo respondsToSelector:@selector(testDelegateMethodTwo)]) {        [self.delegateTwo testDelegateMethodTwo];    }}@end 3、然后在viewController新建此类,进行测试,代码如下

#import "ViewController.h"#import "TestClass.h"#import <objc/runtime.h>@interface ViewController ()<TestDelegate>@property (nonatomic,strong) TestClass *testClass;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    _testClass = [TestClass new];    _testClass.delegate = self;    unsigned int count;    //获取属性列表    objc_property_t *propertyList = class_copyPropertyList([_testClass class], &count);    for (int i=0; i<count; i++) {        const char *propertyName = property_getName(propertyList[i]);        NSLog(@"property---->%@", [NSString stringWithUTF8String:propertyName]);    }        //获取方法列表    Method *methodList = class_copyMethodList([_testClass class], &count);    for (int i=0; i<count; i++) {        Method method = methodList[i];        NSLog(@"method---->%@", NSStringFromSelector(method_getName(method)));    }        //获取成员变量列表    Ivar *ivarList = class_copyIvarList([_testClass class], &count);    for (int i=0; i<count; i++) {        Ivar myIvar = ivarList[i];        const char *ivarName = ivar_getName(myIvar);        NSLog(@"Ivar---->%@", [NSString stringWithUTF8String:ivarName]);    }    [_testClass thisTestMethod];    //获取协议列表    __unsafe_unretained Protocol **protocolList = class_copyProtocolList([_testClass class], &count);    for (int i=0; i<count; i++) {        Protocol *myProtocal = protocolList[i];        const char *protocolName = protocol_getName(myProtocal);        NSLog(@"protocol---->%@", [NSString stringWithUTF8String:protocolName]);    }}- (void)testDelegateMethod{    NSLog(@"12111");}控制台输出如下

2017-02-06 18:34:39.920 RuntimeDemo[10997:466991] property---->innerPrOne2017-02-06 18:34:39.921 RuntimeDemo[10997:466991] property---->delegate2017-02-06 18:34:39.921 RuntimeDemo[10997:466991] property---->outPrOne2017-02-06 18:34:39.922 RuntimeDemo[10997:466991] property---->hash2017-02-06 18:34:39.922 RuntimeDemo[10997:466991] property---->superclass2017-02-06 18:34:39.923 RuntimeDemo[10997:466991] property---->description2017-02-06 18:34:39.923 RuntimeDemo[10997:466991] property---->debugDescription2017-02-06 18:34:39.924 RuntimeDemo[10997:466991] method---->testDelegateMethodTwo2017-02-06 18:34:39.925 RuntimeDemo[10997:466991] method---->thisTestMethod2017-02-06 18:34:39.926 RuntimeDemo[10997:466991] method---->outPrOne2017-02-06 18:34:39.926 RuntimeDemo[10997:466991] method---->setOutPrOne:2017-02-06 18:34:39.927 RuntimeDemo[10997:466991] method---->innerPrOne2017-02-06 18:34:39.927 RuntimeDemo[10997:466991] method---->setInnerPrOne:2017-02-06 18:34:39.928 RuntimeDemo[10997:466991] method---->.cxx_destruct2017-02-06 18:34:39.928 RuntimeDemo[10997:466991] method---->setDelegate:2017-02-06 18:34:39.929 RuntimeDemo[10997:466991] method---->delegate2017-02-06 18:34:39.929 RuntimeDemo[10997:466991] method---->init2017-02-06 18:34:39.930 RuntimeDemo[10997:466991] Ivar---->instanceOne2017-02-06 18:34:39.931 RuntimeDemo[10997:466991] Ivar---->testTwo2017-02-06 18:34:39.931 RuntimeDemo[10997:466991] Ivar---->_delegate2017-02-06 18:34:39.932 RuntimeDemo[10997:466991] Ivar---->_outPrOne2017-02-06 18:34:39.932 RuntimeDemo[10997:466991] Ivar---->_innerPrOne2017-02-06 18:34:39.933 RuntimeDemo[10997:466991] 121112017-02-06 18:34:39.933 RuntimeDemo[10997:466991] protocol---->TestDelegateTwo由此可知此类所有属性与方法,以及该类所遵守的协议在下一篇文章我们将介绍如何运用Runtime进行方法拦截


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