Is it possible to search files of particular extension in the entire device?

In my application, i am trying to find all files of particular extension (like .pdf,开发者_开发问答 .txt, etc) that are stored in the device (either downloaded or transferred from system) and want to list them in table View. Is it possible to do so and if it is then can i associate file of specific extension to get it open in supporting application (any third party plug-ins).I went through numerous documentation but couldn't find the solution. Also how can i index files of these extension for fast search.

Any help is appreciated. Thanks.

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No, it's not possible. You app can't access files of other apps directly.