It will be shown even when nothing could be loaded not due to a network error, and the user can choose to ignore or report it.
Also improve error reporting arguments
Also completely refactor error activity
Also improve some code here and there
For all manually-created images PNG have been kept.
- rename all icon attrs to have a `ic_` prefix
- always use `_24dp` icons, because there is no real difference, since they are vector drawables
- always use the original name found on material.io for icon drawables, as to not create confusion and possibly duplicates. Icon names can still be different from real drawable names, though I have made some of them compliant to this or maybe more meaningul.
- remove duplicate `getIconByAttr()` in ThemeHelper (use `resolveResourceIdFromAttr()`
- use standard icons for `expand_more` and `expand_less` instead of triangles
- use `play_button_outline` instead of custom PNG as play button in VideoDetailFragment (questionable, as there is no shadow anymore)
FocusFinder has glitches when some of target Views have different size.
Fortunately LayoutManager can redefine focus search strategy to override
the default behavior.
