Which pattern should be used for editing properties with modal view controller on iPhone?
- by Matthew Daugherty
I am looking for a good pattern for performing basic property editing via a modal view on the iPhone.
Assume I am putting together an application that works like the Contacts application. The "detail" view controller displays all of the contact's properties in a UITableView. When the UITableView goes into edit mode a disclosure icon is displayed in the cells. Clicking a cell causes a modal "editor" view controller to display a view that allows the user to modify the selected property. This view will often contain only a single text box or picker. The user clicks Cancel/Save and the "editor" view is dismissed and the "detail" view is updated.
In this scenario, which view is responsible for updating the model?
The "editor" view could update the property directly using Key-Value Coding. This appears in the CoreDataBooks example. This makes sense to me on some level because it treats the property as the model for the editor view controller.
However, this is not the pattern suggested by the View Controller Programming Guide. It suggests that the "editor" view controller should define a protocol that the "detail" controller adopts. When the user indicates they are done with the edit, the "detail" view controller is called back with the entered value and it dismisses the "editor" view. Using this approach the "detail" controller updates the model. This approach seems problematic if you are using the same "editor" view for multiple properties since there is only a single call-back method.
Would love to get some feedback on what approach works best.
