Two joined meshes and an armature HELP :(

I almost finished my character for my game and when i got to rigging, the problem came up.When i joined my character’s meshes (Body, shirt and hair) and i rigged him, the body started going tru his shirt!Its like the body is affected more to the armature and the shirt is less.Plz help me idk what to do, and by the way i weight painted it and it still has the same problem! :frowning:

Heres the problem DOWNLOAD (456 kb)

If you can rigg it properly I WILL BE SO THANKFULL :smiley: Please?

P.S I got so mad that i deleted the old rig and saved it :frowning: srry

You need to weight paint after youve joined them together. Oh and make sure they are joined (ctrl + J)