Use MBProgressHUD You can get the whole source code here.
https://github.com/jdg/MBProgressHUD
Hope this helps.
This is a Loading View which is Activity Indicator.
EDIT:
You can add your background view into window while your data is being downloaded in background using
[window addSubview:<backgroundView>.view];
Then once data is downloaded, you can remove the same from window and add your main view controller into window
[<backgroundView>.view removeFromSuperView];
[window addSubview:<mainView>.view];
Hope this helps you.
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