Add support for Android Widgets

[mvysny]

Is it possible for you to add a Widget so that we can drop the slideshow onto the home screen?

I have a wall mounted tablet that has my home controls, and other indicators. It'd be great to have a widget that can display photos. I'm currently using the Animated Photo Widget + - but that only does local, on device photos.

I've purchased PhotoCloud - but would happily pay to unlock a widget feature.

[mvysny]

The Android Widget API is described at https://developer.android.com/guide/topics/appwidgets/overview

Random thoughts below:

• The updatePeriodMillis is a bit problematic since the app will need to update the widgets based on the "new_image_available" event, but that can be solved via forced updates: https://stackoverflow.com/questions/3455123/programmatically-update-widget-from-activity-service-receiver . I can simply set updatePeriodMillis to zero.
• No gestures, therefore no photo pinch-to-zoom, no swipe back for history, but you can still touch the widget to pause the slideshow and reveal EXIF data.
• Android layouts enforced. That's a pity since android layouts are defined in XML and they simply suck. But I can always start with something simple, like a basic ImageView
• Remote Android layouts enforced, which further limits what we can draw. Can't even use ImageSwitcher. Definitely use ImageView
• The memory considerations? The slideshow uses a considerable amount of memory, causing the widget to use lots of memory too. Let's experiment on this: maybe Android will kill the app frequently in order to conserve memory, especially on lower-end phones? This needs to be explained to the user.

Notes to myself:

• Start by copying out DaydreamService but much simplified - no clock, no EXIF, just an ImageView and a TextView in case of errors.
• If there is a widget on screen, don't allow starting a new slideshow, to conserve memory.
• Only allow 1 widget max.

[AXEBro]

This is excellent, thank you!