列出Objective-C对象的选择器

Question

我有一个对象，我想列​​出它响应的所有选择器。感觉这应该是完全可能的，但我找不到API。

Answer 1

这是一个基于运行时C函数的解决方案：

class_copyMethodList返回给定可从对象获取的Class对象的类方法列表。

#import <objc/runtime.h>

[..]

SomeClass * t = [[SomeClass alloc] init];

int i=0;
unsigned int mc = 0;
Method * mlist = class_copyMethodList(object_getClass(t), &mc);
NSLog(@"%d methods", mc);
for(i=0;i<mc;i++)
    NSLog(@"Method no #%d: %s", i, sel_getName(method_getName(mlist[i])));

/* note mlist needs to be freed */

Answer 2

我想通常你会想在控制台中这样做，而不是用调试代码混乱代码。这是在lldb中调试时如何做到这一点：

（假设一个对象t）

p int $num = 0;
expr Method *$m = (Method *)class_copyMethodList((Class)object_getClass(t), &$num);
expr for(int i=0;i<$num;i++) { (void)NSLog(@"%s",(char *)sel_getName((SEL)method_getName($m[i]))); }

Answer 3

Swift也可以这样做：

let obj = NSObject()

var mc: UInt32 = 0
let mcPointer = withUnsafeMutablePointer(&mc, { $0 })
let mlist = class_copyMethodList(object_getClass(obj), mcPointer)

print("\(mc) methods")

for i in 0...Int(mc) {
    print(String(format: "Method #%d: %s", arguments: [i, sel_getName(method_getName(mlist[i]))]))
}

输出：

251 methods
Method #0: hashValue
Method #1: postNotificationWithDescription:
Method #2: okToNotifyFromThisThread
Method #3: fromNotifySafeThreadPerformSelector:withObject:
Method #4: allowSafePerformSelector
Method #5: disallowSafePerformSelector
...
Method #247: isProxy
Method #248: isMemberOfClass:
Method #249: superclass
Method #250: isFault
Method #251: <null selector>

使用运行iOS 9.2，Xcode版本7.2（7C68）的6s模拟器进行测试。

Answer 4

这样的东西应该工作（只需将它放在你很好奇的对象中）。例如，如果你有一个委托的对象，并想知道什么是'钩子'可用，这将打印出消息，为你提供线索：

-(BOOL) respondsToSelector:(SEL)aSelector {
    printf("Selector: %s\n", [NSStringFromSelector(aSelector) UTF8String]);
    return [super respondsToSelector:aSelector];
}

请注意，我在iPhone Developer's Cookbook中发现了这一点，所以我不能相信！例如，我从实现协议UIViewController的<UITableViewDelegate, UITableViewDataSource>获得输出：

Selector: tableView:numberOfRowsInSection:
Selector: tableView:cellForRowAtIndexPath:
Selector: numberOfSectionsInTableView:
Selector: tableView:titleForHeaderInSection:
Selector: tableView:titleForFooterInSection:
Selector: tableView:commitEditingStyle:forRowAtIndexPath:
Selector: sectionIndexTitlesForTableView:
Selector: tableView:sectionForSectionIndexTitle:atIndex:
...
...
etc.,etc.

Answer 5

从JAL的答案中获取灵感，在Swift中你可以做到：

extension NSObject {
    var __methods: [Selector] {
        var methodCount: UInt32 = 0
        guard
            let methodList = class_copyMethodList(type(of: self), &methodCount),
            methodCount != 0
        else { return [] }
        return (0 ..< Int(methodCount))
            .flatMap({ method_getName(methodList[$0]) })
    }
}

Answer 6

ARC实现

SomeClass *someClass = [[SomeClass alloc] init];    

//List of all methods
unsigned int amountMethod = 0;
Method *methods = class_copyMethodList(someClass, &amountMethod);

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

    printf("\t method named:'%s' \n", sel_getName(method_getName(method)));
}

free(methods);