Hello,
We have carefully read and understood your requirement.
To begin with, since you have specifically asked for an ipad App, may we mention that to host an ipad App in the App store you must have a developer account with apple which comes at about $100 a year. Having that account, you would be in a position to provide us a with a provisioning profile which would be necessary for the development.
That said, since the app is to work offline, it is important to arrive at the format in which the contents would be passed on to the app for local storage. We would recommend XML format for this. JSON could be used as an alternative. However, for either case your Joomla site should have the functionality to provide all content data in the format that is approved. If you do not have such functionality in your site, we could also develop that for you at an additional cost.
The app would check for and download the data at the time of installation and thereafter it would be accessible locally as offline data.
As for updates, each time the app is launched, we will make it check on the live site (if a net connection is available at the time of launch). The Joomla installation should also be able to return the modification date of the last changes. Thus if the returned date is newer that the date stored on the local data, the user would be informed that an update is available and requested to update the locally stored data.
Regards
Aurora Media