oc动态方法绑定

绑定多个参数

    //传递三个及以上的参数
- (id)performSelector:(SEL)selector withObjects:(NSArray *)objects
    {
        // 方法签名(方法的描述)
        NSMethodSignature *signature = [[self class] instanceMethodSignatureForSelector:selector];
        if (signature == nil) {

            //可以抛出异常也可以不操作。
        }

        // NSInvocation : 利用一个NSInvocation对象包装一次方法调用（方法调用者、方法名、方法参数、方法返回值）
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature];
        invocation.target = self;
        invocation.selector = selector;

        // 设置参数
        NSInteger paramsCount = signature.numberOfArguments - 2; // 除self、_cmd以外的参数个数
        paramsCount = MIN(paramsCount, objects.count);
        for (NSInteger i = 0; i < paramsCount; i++) {
            id object = objects[i];
            if ([object isKindOfClass:[NSNull class]]) continue;
            [invocation setArgument:&object atIndex:i + 2];
        }

        // 调用方法
        [invocation invoke];

        // 获取返回值
        id returnValue = nil;
        if (signature.methodReturnLength) { // 有返回值类型，才去获得返回值
            [invocation getReturnValue:&returnValue];
        }

        return returnValue;
    }

执行objc_msgsend

- (void)ObjcMsgSend {
    NSString *str = @"字符串";
    NSNumber *num = @20;
    NSArray *arr = @[@"v1", @"v2"];

    SEL sel = NSSelectorFromString(@"ObjcMsgSendWithString:withNum:withArray:");

    ((void (*) (id, SEL, NSString *, NSNumber *, NSArray *)) objc_msgSend) (self, sel, str, num, arr);
}
// 执行方法
- (void)ObjcMsgSendWithString:(NSString *)string withNum:(NSNumber *)number withArray:(NSArray *)array {
    NSLog(@"%@, %@, %@", string, number, array[0]);
}