How can i keep one child by default when my page loads?

hi guys,

i want to keep Default one child when my page loads.i have arraycollection of the container.in that i have used repeater whose dataprovider is arraycollection.what i have to do for that? can i put some code in init() function.but which code i should put in it?

any suggestions.pl forward.thank u in advance.

Thanks & Regards