Technically it depends on the data (e.g. Podcast activity lets the user delete downloaded podcasts) but in general, no. Uninstalling and reinstalling, or using the Clear Data button inside the App Info settings, are the only ways to do that currently.
What kind of app is it, and what kind of data did you want deleted?
@lorne Hi! I have this issue when deleting YouTube videos from my playlists. The users only see "video deleted" message. If they clear the cache (manually), the list is OK again.
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What kind of app is it, and what kind of data did you want deleted?
Downloaded feed data is automatically purged/truncated when it reaches a certain level, so no, it won't grow forever.