Main Screen Mockup

 I did some test with Yahoo Finance Api.. trying to understand, which data, it is possible to retrieve fast from their service and which is slowly, also because it is huge.
What I would like to achieve in this application is  a fast, responsive interface, designed to mitigate the delay during data retrieval.
A good organized application can help to reduce this problem and make users happy to use the application.

After this step, I did a mockup, with pencil, of the main screen of my application:

Let me show you how it should work... using the 3 bullet on the mockup

• bullet 1: this is the zone where chart of a selected company is displayed. At the first launch will display the chart of the first present company or, a message if none company is registered. As you can see, there is also on the top right a combo box. This combo box contains some prefixed , period: 1 week, 1 day, 1 month, 1 year ecc. Changing the combobox will update the chart accordingly to the selected period. I don't know if I will use a combo box, but it's just for the idea.  I would like also to change the period, simply scrolling in or scrolling out on the chart.
• bullet 2: The list of your selected stock quote companies. At the launch of the application this table should be populated asynchronously .. putting every line , one by one, after every download of the information from a company, and making user informed of the in progress operation. Clicking on one of this row will update the chart.
• bullet 3: a toolbar for handling: add of a new company in the table, remove of an existing company, fullscreenmode. Fullscreen will be a mode to use all the screen for displaying the data of only one selected company with a chart that will take 90% of the screen. It needs a new mockup only for this.

I will try to reduce call to yahoo service whenever is possible with a local caching mechanism like save the data displayed on the table, save the data displayed on a chart for a company... So if I know that the data is locally present, I will not fetch it from Yahoo, otherwise I will fetch, display and save it locally.

Other Features..
Yes, it is not just finished here but, my time is limited so I need to proceed step by step and reach some milestones before proceed with other feature..
I prefer to create a working program with less feature but robust than an application with many feature and bugs.