performSelector的返回值是什么:如果我传递了一个返回基元类型(在对象上)的 Select 器,比如NSDateComponents上的"week"(将返回int)?
performSelector的返回值是什么:如果我传递了一个返回基元类型(在对象上)的 Select 器,比如NSDateComponents上的"week"(将返回int)?
使用NSInvocation返回浮点值的示例如下:
SEL selector = NSSelectorFromString(@"someSelector");
if ([someInstance respondsToSelector:selector]) {
NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:
[[someInstance class] instanceMethodSignatureForSelector:selector]];
[invocation setSelector:selector];
[invocation setTarget:someInstance];
[invocation invoke];
float returnValue;
[invocation getReturnValue:&returnValue];
NSLog(@"Returned %f", returnValue);
}