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Viewing Spending Categories
Design 2
Learnability
Most of the options of this design are derived from existing designs of many common smartphone menus. Taking a picture of a receipt and browsing through old receipts is similar to IPhone camera interface and entering and editing receipt and report details is similar to its settings menu. This aspect of the design makes it very learnable for smartphone users. The other elements that do not have a parallel in common menus or application are sufficiently documented, with the buttons stating exactly which action should be taken.
Visibility
The visibility of this interface is not very high. In most menus, most of the screen is dedicated to showing the relevant information and the important controls are small and in the bottom of the screen. The "back" button, when exists, is very small and appears in the to left corner of the screen. Most actions have appropriate affordances, but some do not. For example, the list in 1.2.2 appears like it is editable by clicking on it, when in fact you can only edit it by adding items through the menu on the top.
Efficacy
In this design, the top storyline contains all the common actions, and the bottom ones show special options. Most of the actions can be done very efficiently using this design - a receipt can be captured and categorize in just two steps. However, submitting the report is not very efficient, since the user is prompted to approve the submission.
Error Prevention
This design does not prevent the user from making most errors. The different fields in the receipt categories do limit the types of input a user can insert, but common mistakes will probably include mis-categorizing a receipt, entering the wrong amount, or attaching the wrong picture to the receipt. Mis-categorizing a receipt or entering the wrong amount can be fixed by looking up the receipt item under the report and editing it, but attaching the wrong picture would force the user to delete the receipt entirely and create a new one.