I have two Activities: SearchActivity (search for items) and DownloadsActivity (show downloads). How do I show ProgressBar in DownloadsActivity?

Question

I'm writing a simple downloader app which has two activities: SearchActivity: shows a list of items you can download given a query. pressing an item should start downloading the item, but stay in the SearchActivity. Pressing an item currently runs an AsyncTask to handle the downloading logic

DownloadsActivity: shows a list of currently downloading items and ProgressBars (with percent) for each item.

I've set everything up except the ProgessBars. I'm wondering what is the best way to have the ProgressBars in the DownloadsActivity update correctly. Within the download AsyncTask run within the SearchActivity, how do I update the respective progressbar in DownloadsActivity if DownloadsActivity is being viewed?

Answer 1

You should likely use the Service component for the downloads purpose. This would allow you to run AsyncTasks (or just separate threads) from within the Service itself. Afterwards, the status of the particular download may be retrieved by any Activity by invoking some method (written by you) on the Service object which, in fact, is managing all the downloads. Oh, and in the same way you may want to start downloads.

BTW, to retrieve Service instance object from within Activity, you need to bind to the service first and then get its instance object using the IBinder interface. Further info on Services could be found here.