** UPDATED with picture
Below is a simple mockup for a spending tracker mobile app (for frequent travelers) that i built. Each of the 3 gray boxes are inputs (name, amount, currency). A sample input would be "lunch", "12.75", "dollars". All three are necessary for my app and they must be in that order.
I am considering the following options/variations on the user interface, and want to get some opinions. (each option below gets a little more innovative than the previous)
Each input box is a text box, and the user can input free form. The middle input for "amount" is a decimal pad (for only numbers).
The first and last input boxes are combo boxes. They have a little triangle button at the end of the input box that indicates you can get a pull down with possible values. Also, if you choose to type, this list will get filtered.
I am considering using a UIPickerView (iOS), which is the wheel selector interface on the iPhone. It looks like a casino slot machine interface. The urbanspoon app is famous for using this interface. I like it because it is so intuitive and you scroll through suggestions, then stop on the one you want. however, i'll have to code a custom row that you can input your own name.
Typeahead/autocomplete. I don't like this because the user has to type in common categories all the time.
I'm thinking of creating a new intuitive interface that is similar to the wheel selector described above. It will look like a regular textField. But it will have indicator arrows above and below the textField. When you touch the textField, a wheel selector fades into view. I'm not going to use the standard wheel selector provided by iOS. I'm going to create one that is slightly translucent, and seems to fade away further it is from the actual textbox. You can scroll through suggestions, then stop on the one you want. Note that the keyboard will display, since you can edit the textField. Once you close the keyboard, the wheel selector will fade away, and you're left with a plain textField with indicators that you can scroll if you touch the textField.
The typical use case is as follows: The user will type in freeform the first few times. Then the user will likely choose from his/her most common categories.
What are people's reactions to my potential options?