Android: Task application Form edit/view pattern?

Question

I am writing an android application that manages a list of Todo tasks. So each task have properties such as title, due date, priority, importance and so on.

So there will be a list of all the tasks, and then when the user selects a task, he should be able to view/edit the task, here's where I am confused about which "pattern" to use.

Looking at the stock android apps on my Nexus S with Jelly Bean, there are a couple of patterns:

1. Calendar App Upon clicking on a calendar entry, a view mode is displayed, with the edit and delete button in the action bar, clicking on edit will make all the fields editable.

   

2. Contacts App Quite similar to the above, besides that, I need to click Menu->Edit, as there are no edit icon in the action bar

   

3. Alarm Clock App This is totally different, and represent what I thought to be a better interface, basically every field is displayed as an item in the List, and then clicking each of them will create a popup, with an OK and Cancel button.

   

4. Last is the Tasks application, which does away with the View mode, and just changes into Edit mode straight away:

   

What are the guidelines of which type of UI to choose?

Answer 1

When thinking about UI patterns with this much subtlety it helps to think about what frequency of use a particular feature will get. For example. In the Calendar app the majority of use I imagine will be adding new events and viewing (or accessing) existing events. When the user's primary motive is to find information from existing events, a non-editable view makes sense because it adds the least distraction for the majority of their tasks. Copying text on an editable view for example would force the virtual keyboard to open and add an extra layer of interaction. Therefore the decision to use an edit button to edit the event in this case makes sense.

When struggling with these types of decisions I would think about the context your users are in and what frequency they perform each task.

Google's design docs may also provide some inspiration in helping you choose the right pattern you're after.