Runtime Method 介紹:

typedef struct objc_method Method;

struct objc_method{

SEL method_name;  //方法的名稱

char *method_typesE;//引數和返回型別的描述字串

IMP  method_imp;   //方法具體實現的指標

}

// 函式呼叫，但是不接收返回值型別為結構體

method_invoke

// 函式呼叫，但是接收返回值型別為結構體

method_invoke_stret

// 獲取函式名

method_getName

// 獲取函式實現IMP

method_getImplementation

// 獲取函式type encoding ,其結果是一串值

method_getTypeEncoding

// 複製返回值型別

method_copyReturnType

// 複製引數型別

method_copyArgumentType

// 獲取返回值型別

method_getReturnType

// 獲取引數個數

method_getNumberOfArguments

// 獲取函式引數型別

method_getArgumentType

// 獲取函式描述

method_getDescription

// 設定函式實現IMP

method_setImplementation

// 交換函式的實現IMP

method_exchangeImplementations

小提示:

void *memset(void *s, int ch, size_t n);

函式解釋：將s中前n個位元組 （typedef unsigned int size_t ）用 ch 替換並返回 s 。

memset：作用是在一段記憶體塊中填充某個給定的值，它是對較大的結構體或陣列進行清零操作的一種最快方法[1]  

- (void)getAllMethods{
    //獲取所有方法
    unsigned int outCount = 0;
    Method *methods = class_copyMethodList([self class], &outCount);
    for (int i = 0; i<outCount; i++) {
        //1.獲取方法
        Method method = methods[i];
        SEL methodName = method_getName(method);
        NSLog(@"方法名:%@",NSStringFromSelector(methodName));
        
        //2.獲取方法裡的輸入引數
        unsigned int argCount = method_getNumberOfArguments(method);
        char argName[512] = {};
        for (int j = 0; j< argCount; j++) {
            method_getArgumentType(method, j, argName, 512);
            NSLog(@"引數型別:%s",argName);
            memset(argName, '\0', strlen(argName));
        }
       
        //3.獲取方法返回值型別
        char retType[512] = {};
        method_getReturnType(method, retType, 512);
        NSLog(@"返回型別值型別:%s",retType);
        
        //4.輸出返回型別輸入引數混合編碼格式: "返回值型別"+基地址偏移+"@"+基地址偏移+":"+基地址偏移+"輸入引數1型別"+基地址偏移+"輸入引數2型別"+基地址偏移+....
        NSLog(@"返回型別輸入引數混合編碼:%s",method_getTypeEncoding(method));
    }
    free(methods);
}
 

method_invoke的介紹

Method method = class_getInstanceMethod([ViewController class], NSSelectorFromString(@"getAllMethods"));

    method_invoke([ViewController class], method);

<===> ((void (*)(id,SEL))objc_msgSend)((id)self,NSSelectorFromString(@"getAllMethods"));

//列印結果

2016-03-25 13:20:11.598 runtimeMethodDemo[1610:187967] 方法名:getAllMethods

2016-03-25 13:20:11.600 runtimeMethodDemo[1610:187967] 引數型別:@

2016-03-25 13:20:11.600 runtimeMethodDemo[1610:187967] 引數型別::

2016-03-25 13:20:11.600 runtimeMethodDemo[1610:187967] 返回型別值型別:v

2016-03-25 13:20:11.601 runtimeMethodDemo[1610:187967] 返回型別輸入引數混合編碼:[email protected]:8

2016-03-25 13:20:11.601 runtimeMethodDemo[1610:187967] 方法名:setVc:

2016-03-25 13:20:11.601 runtimeMethodDemo[1610:187967] 引數型別:@

2016-03-25 13:20:11.601 runtimeMethodDemo[1610:187967] 引數型別::

2016-03-25 13:20:11.602 runtimeMethodDemo[1610:187967] 引數型別:@

2016-03-25 13:20:11.602 runtimeMethodDemo[1610:187967] 返回型別值型別:v

2016-03-25 13:20:11.602 runtimeMethodDemo[1610:187967] 返回型別輸入引數混合編碼:[email protected]:[email protected]

2016-03-25 13:20:11.602 runtimeMethodDemo[1610:187967] 方法名:noRetNoArg

2016-03-25 13:20:11.602 runtimeMethodDemo[1610:187967] 引數型別:@

2016-03-25 13:20:11.603 runtimeMethodDemo[1610:187967] 引數型別::

2016-03-25 13:20:11.603 runtimeMethodDemo[1610:187967] 返回型別值型別:v

2016-03-25 13:20:11.605 runtimeMethodDemo[1610:187967] 返回型別輸入引數混合編碼:[email protected]:8