I have a need to allow a user to select x of n from a list of elements. The specific example is 9 elements out of perhaps 20.
This would be in the context of a settings context (rather than a form one would be filling out).
What I've come up with thus far. Option #1:
item 1 > item 2 > item 3 > item n >
That screen would have the already selected items highlighted. Clicking on an item would take you to that item's screen where you'd see the traditional on/off slider control as part of the details for that item:
< back on [ off ]
That seems to adhere to touch UI principles, but seems clumsy. You have to flip between screens and if you try to select #10 when you can only have 9 selected, then we have to notify you to go back, pick another, unselect, return, then pick this one again. Tedious.
This would be more of a traditional check list:
[ 1 ] item 1 > [ ] item 2 > [ 2 ] item 3 > [ ] item n >
tapping the widget will select it by giving it a number.
The main advantage is that you don't have to flip between pages to select the items.
Drawbacks would be that the check boxes could interfere with the scrolling. The other issue is the numbering. If I unselect #2, then the other selected ones should renumber (3 becomes 2, 4 becomes 3, etc.). Certainly easy to do, but not sure if that would be a bad UX.
Is there a preferred way to handle this on a touch device? Any other suggestions or examples seen in the wild?