Folio

Folio is a PDF reader built around reading rather than file management. The page fills the screen, the controls stay out of the way until you tap the centre, and tapping the edges turns the page. Position is saved on every page turn, so a document reopens where you stopped, even after a force stop or a reboot.

It is local by design: no store, no account, no ads, no analytics, and reading works offline. The only network feature is an optional web search that loads Google or DuckDuckGo in a WebView. The app never reads or scrapes the results - it only catches a tap on a PDF link, and the page gets no access to files or app code. A downloaded file opens as a preview and enters the library only when you add it.

Rendering uses the framework PdfRenderer, so there is no native library in the APK and no licence baggage. Memory is kept in check deliberately: only the visible page and its neighbours are rendered, a rendered page is capped at 8 million pixels, and the bitmap cache is an LRU bounded by bytes. That holds up on 600-page and 914-page books.