How to list file and folders of various dropbox user account in ios app.

No, the app authorization flow on iOS should only be processed via the official Dropbox for iOS app, or via an OAuth flow on the Dropbox web site. We recommend using the official SDK, which handles most of the work for you:

https://www.dropbox.com/developers/core/sdks/ios

The tutorial covers listing files and folders:

https://www.dropbox.com/developers/core/start/ios

Thanks for the reply
I followed all the steps in that, i am able to list the folders from a account which i have created that is linked with the app.
I want to list the folders or files from other dropbox user account using their credentials.Can it be done?

No, your app shouldn't directly handle any user credentials. When you release your app to other users, they can link it to their own accounts just like you linked it to yours.

"When you release your app to other users".
What does that mean,Can you elaborate it?
How other users can link,can we check that by creating other account of mine ?

I mean that when you give your app to other people to use, for example, by releasing your app on an app store or marketplace. The API is designed with the intention that each person that uses it would link their own account. When they first start using your app, they can use the app authorization flow it implemented to link their account.