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]);
}
