A generic answer:
Ask your developer.
As a designer
If you want to control the sikn, for example uploading a new color scheme for the icons, and you can just upload a new set of icons (in the correct size and format)... export all the circle and the pause / stop graphic all together.
As a developer
Here is the tricky part.
I asked in StackOverflow chat, and someone responded this:
@Rafael just send whole psd file
but regarding that exact design: I never worked on android apps, but at least as far as CSS goes that design requires no assets, maybe exported play/pause buttons as svg, but even those seem pretty generic.
An svg or a symbol font like fontawesome/wingdings/etc would be all i would imagine a design like that would need.
Hum. Do you like to export the parts as you need them?
@Rafael I try to make as much of the design as I can with code only, avoiding unnecessary assets - so yes - I just extract what I need from the design.
I think this depends on 2 things. 1) How much do you know about developing and 2) How much control each person needs.
1) I recently had a web project where I asked one person to give me a photo. He use it on a mockup in Ilustrator and exported it from there... Of course it was exported at the wrong resolution and in cmyk. I asked the original photo after that.
But if you really know how to do it, it is helpfull to have a real teamwork.
2) For example. In this chat cimmanon coments about fontawesome. Developers are used to use online resources that works in diferent way than designer´s resources. This particular one is a font set that gives you icons that they just can link and it will be inserted in the design. This gives them control on the project as they need it.
But as I comented, if you want acces to a folder where you need to change icons to experiment without touching the code, do it that way.