Design considerations, particular to Android Wear.
With the introduction of Marshmallow, and the increase uptake of wearable devices. The need to build flexible designs is even more important. With devices now not just following a single standard form it is more important to follow the complete Assets Requirements, to complete the variety of forms.. Most of the complexities of supporting these different devices is taken care of at a system level, but bear in mind different screen types when designing custom full screen apps.
Use the Android Wear emulator to test both square and round devices, and note that WatchViewStub is available to activities to detect whether a square or round device is being used.
A core set of standard assets may need to be provided depending on your card design: app icon, background image or images, action icons, and action confirmation animations. Of course, your specific design may necessitate other assets. Background images should be provided in landscape format at least 600px width for notifications that include pages of cards, since the system automatically adds a parallaxing effect.Peek Card Readability
Test your card layout to ensure that useful information is conveyed in the peek state on the Home screen. The main message of the card should be readable in the peek state, particularly for contextual cards. Content that requires an interaction to be read, for example a long message, should be cropped appropriately to provide an affordance to the user to swipe the card to read more.
To understand more about Asset Requirements get the Design Methods book.
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