Sometimes you, the Android developer, will work with designers who have the time and knowledge to think of everything. They create complete, detailed designs for every screen and interaction. They cover both web, iOS and Android. They regularly use both Android and iOS themselves. They understand the strengths and conventions of each platform.
These projects are delightful. Unfortunately, all projects are not like this.
Some designers are very busy, so they have to pick their battles: they only have time to establish platform-agnostic wireframes and guidelines.
Other designers are inexperienced, or very web-centric.
Or perhaps they know iOS very well, but are unfamiliar with Android.
When you end up in this situation you can either A: bemoan the situation, and let the project falter. Or B: apply some ownership and do your best to help out. I suggest you try the latter.
Ways to help your designer succeed
Collaborate closely. Work together from day one. “Throw the design over the wall” is risky even when you have worked well together for extended periods. If the designer is busy and pulled in several directions, ask the project manager to carve out as much time together as possible.
Suggest the following default mode: “Let’s follow the Material Design guidelines as far as possible. We’ll make deviations only where it makes sense for our app”. Google’s own guidelines are comprehensive and detailed. And constraints and conventions help: honest designers will tell you that facing a completely blank canvas is scary.
If the designer is very web-centric, it’s your job to suggest alternative navigation patterns and UI conventions to make their designs work well in native app form. Be constructive and helpful. Provide positive and well-reasoned options, avoid negative critique.
If the designer knows iOS well, the work is simpler. The platforms have become fairly similar in design and capability — you may be able to map their iOS design directly to Android. If the designer has no experience as an Android user, consider giving them a loaner Android phone for a while.
Synch up often, especially early on. “Hi, do you have five minutes? I just want to know if this screen looks right to you.” Sit down and polish the user interface together. This will let you catch issues early, and you will establish mutual trust and rapport.
Prerequisite: design-aware developer
The tactics outlined above essentially require you to carry some of the designers workload. You can’t do this effectively if you have zero design skills yourself.
You need enough grounding in UI and UX principles to have a rudimentary “designer’s eye”. You should be able to catch obvious issues yourself: unaligned elements, low contrast, inconsistent layout and typography, unclear copywriting. The basics. If you take care of this, you free up your designers time for more high level work.
Also, if you know a bit of design lingo you will communicate more effectively. You become able to understand your designers general intent. At that point you will no longer require spoon-fed specifications.
Finally: be humble. The designer likely respects your craft. That should be mutual. You may know enough about design to be dangerous, but understand that there are factors and tradeoffs you do not see. Some design choices seem irrational or emotional but are based on gut feel and tons of experience.
If you are able to work this way, you will establish rapport and trust with the designer more rapidly, and they will be able to lean on you for support.