Android: should I launch a new activity or show a dialog?

Let's say I want my app to dis开发者_StackOverflow社区play a file browser. Are there any significant advantages or disadvantages to having this file browser extend Dialog instead of extending Activity? I was unable to to find anything useful in the documentation; any input?

Thanks

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To be honest, it's all about user experience. So if they are just going to be selecting a file and that's it, then I would recommend using a Dialog. If you want it to do a lot more than just selecting a file and then disappearing, then definitely open it up in a new Activity.