获取 Objective-C 类或实例的所有方法

Question

在 Objective-C 中，我可以测试给定的类或实例是否响应某些选择器。但是如何查询一个类或实例的所有方法或类的属性（例如所有方法或属性的列表）？

Answer 1

这可以通过 objc_method_list 实现。为了枚举您的方法，您必须事先注册所有方法。

这个过程很简单：在你声明你的函数之后，你可以创建一个 objc_method 的实例并注册函数名。然后将 objc_method 添加到 objc_method_list 中，最后将 objc_method_list 传递给 class_addMethods..

这是一个帮助您入门的链接： http://theocacao.com/document.page/327

Answer 2

您需要使用 Objective C 运行时方法，请参见此处：https://developer.apple.com/reference/objectivec/objective_c_runtime

Answer 3

您可以做到这一点，它在https://developer.apple.com/library/mac/documentation/cocoa/Reference/ObjCRuntimeRef/index.html 上有很好的记录

要获取一个类的所有实例或类方法，您可以使用class_copyMethodList 并遍历结果。一个例子：

 #import <objc/runtime.h>

/**
 *  Gets a list of all methods on a class (or metaclass)
 *  and dumps some properties of each
 *
 *  @param clz the class or metaclass to investigate
 */
void DumpObjcMethods(Class clz) {

    unsigned int methodCount = 0;
    Method *methods = class_copyMethodList(clz, &methodCount);

    printf("Found %d methods on '%s'\n", methodCount, class_getName(clz));

    for (unsigned int i = 0; i < methodCount; i++) {
        Method method = methods[i];

        printf("\t'%s' has method named '%s' of encoding '%s'\n",
               class_getName(clz),
               sel_getName(method_getName(method)),
               method_getTypeEncoding(method));

        /**
         *  Or do whatever you need here...
         */
    }

    free(methods);
}

您需要对该方法进行两次单独的调用。一个用于实例方法，另一个用于类方法：

/**
 *  This will dump all the instance methods
 */
DumpObjcMethods(yourClass);

在元类上调用相同的方法会给你所有的类方法

/**
 *  Calling the same on the metaclass gives you
 *  the class methods
 */
DumpObjcMethods(object_getClass(yourClass) /* Metaclass */);

Answer 4

除了 Buzzy 的回答，出于调试目的，您可以使用 -[NSObject _methodDescription] 私有方法。

在 lldb 中：

(lldb) po [[UIApplication sharedApplication] _methodDescription]

或在代码中：

@interface NSObject (Private)
- (NSString*)_methodDescription;
@end

// Somewhere in the code:
NSLog(@"%@", [objectToInspect performSelector:@selector(_methodDescription)]);

输出将如下所示：

<__NSArrayM: 0x7f9 ddc4359a0>:
in __NSArrayM:
    Class Methods:
        + (BOOL) automaticallyNotifiesObserversForKey:(id)arg1; (0x11503b510)
        + (id) allocWithZone:(_NSZone*)arg1; (0x11503b520)
        + (id) __new:::::(const id*)arg1; (0x114f0d700)
    Instance Methods:
        - (void) removeLastObject; (0x114f669a0)
        - (void) dealloc; (0x114f2a8f0)
        - (void) finalize; (0x11503b2c0)
        - (id) copyWithZone:(_NSZone*)arg1; (0x114f35500)
        - (unsigned long) count; (0x114f0d920)
        - (id) objectAtIndex:(unsigned long)arg1; (0x114f2a730)
        - (void) getObjects:(id*)arg1 range:(_NSRange)arg2; (0x114f35650)
        - (void) addObject:(id)arg1; (0x114f0d8e0)
        - (void) setObject:(id)arg1 atIndex:(unsigned long)arg2; (0x114f99680)
        - (void) insertObject:(id)arg1 atIndex:(unsigned long)arg2; (0x114f0d940)
        - (void) exchangeObjectAtIndex:(unsigned long)arg1 withObjectAtIndex:(unsigned long)arg2; (0x114f8bf80)
        ......
in NSMutableArray:
    Class Methods:
        + (id) copyNonRetainingArray; (0x11ee20178)
        + (id) nonRetainingArray; (0x11ee201e8)
        + (id) nonRetainingArray; (0x120475026)
        + (id) arrayWithCapacity:(unsigned long)arg1; (0x114f74280)
        ......