The best interface for selecting many objects from another set of many objects?
Let's say you're developing a travel site and you want your users to create a Potential Destinations list so that you can send them hot deals for those places only.
This list consists of an arbitrary number of cities selected from the universe of cities. The universe has (say) 1000 cities, and the average list will consist of (say) 20 cities.
What interface would you offer users to manage their Potential Addressees list?
BONUS QUESTION: How does your answer change if you need to give users a City RANK (in order of preference) option in their "potential assignments"?
My thought is to have an interface with two widgets: an autocomplete text box on the left and a list box on the right. The text box autocompletes by city name and when you select something, it is removed from the text box and added to the list. You can remove items from the list by clicking the "X" next to them and drag to reorder.
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This is only MHO, but:
In terms of widgets, if you can afford on-screen real estate, you might be best off choosing an initial selection screen with two side-by-side boxes, with moving here and button movements.
The list on the left (of cities) can be swapped using a combo box with some search functions.
However, you will probably want the list on the left, because then you can order it into a table (for example, add state, country, etc.) and offer a means to sort within that column. So, for example, if I want to find all resorts in Portugal, I can easily find them. With autocomplete, I have to figure them out for myself.
If you do have room, you can go with three boxes or a tree view for the left box to suggest some categories.
Of course, if you do all this with flash and can process faster, then perhaps you can go with a standard shopping cart approach.
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Why stop at text boxes?
Here's my fantastic, time-consuming idea (since you didn't specify a time limit ... and there is a lot of snow, so I'm thinking of sandy beaches).
I am thinking of a nice google map with overlay. You can find a city and it will send you to the general area of that city. Zooming close enough to a city will place various markers on the map with the landmarks of that city and load some commercials. Imagine looking for Miami and it is approaching the Miami area with photos of beaches, sand and other goodies. Next to the map you will have "Add to my destinations" which will add the list to the recipient list. This list will always be available on the right side. Clicking on an item in the list takes you to that city on the map. Each item will have an [x] to remove it from the list. The ranking will be done using drag and drop.
The idea is to get your users interested in these places and see some of these places. Since this is a travel website, I expect some of this data to be available now, I'll just write it.
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I would have two lists: one on the left with all possible unselected choices in some useful order (alphabetically) and one on the right for the selected destinations.
I would allow users to drag items from one side to the other, and also drag up and down the right hand list if necessary
Some center buttons may also provide equivalent keyboard controls.
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