cisco 3750 - stacking and vlans

I have two WS-C3750X-12S-S    switches stacked.

I created a vlan giving

 vlan 10

name test

 then i gave the vlan 10 an interface ip address.

 "interface vlan 10

ip add 10.20.4.1 255.255.255.0"

 BUT the problem is I cant ping this inteface even being inside the switch.

There is an ip for the vlan 1 and i can ping that ip.

 "sh vlan brif" - shows vlan 10 is active

I tried "no shutdown" in the vlan interface. No result

 ip routing is also enabled.

 I have been doing intervlan routing with 3750. but this is the first time with 2 switches stacked. Is stacking to do anyting with vlans.

Check the output of show interface vlan 10.

 I am sure it won't be UP and UP.

 The reason might be because there is no switch port elonging to VLAN 10 as pointed in the above post.

Connect a PC on an interface. Configure that interface for VLAN 10. Wait untill the physical interface comes up and then again check the output of show interface vlan 10. Now it should be up and up  and you should be able to ping it from the swithc and other devices as well as long as they have IP connectivity.

Conclusion - there should be an interface assigned to that VLAN and that particular physical interface should be up. Only then the WS-C3750V2-48PS-S    VLAN interface would come up.