I'm designing iOS and Android apps full-time for over a year now. A couple of tips from me:
- He's very right about previewing on the device. I like xScope better than Silkscreen, because it can stream anything, both file, or screen region, and overall it's a nice designer's utility belt. There's nothing like that for android, at least I haven't found anything that works, and Android needs this even more, because it usually uses OLED, not LED screens.
- Unless you have plenty of time and very little UI, you shouldn't optimise for @1x design. The key is to design @2x assets that are ALWAYS even. Everything has to be 2 pixels or even-sized, every line, button size, coordinate and so on. To achieve crisp, 1px lines on Retina, you can do 1px strokes (for example, on button), but you have to make sure they are inside evenly sized (round-)rect, and twice as "strong" (darker, lighter, etc.), so that when PhotoShop resizes that 1px line, its darkness is mixed with the next pixel inside the button, and looks right on standard resolution.
- Another app I highly recommend: Slicy. Saved me many hours of work, and can automate the whole process of exporting assets.
- Keep the asset naming consistent, that will make developers happier and more productive.
- Learn at least the basics of iOS and Android app development. Basics are easy, and you will learn how developers layout the interfaces. That will get you thinking while designing, what assets will allow developers to make the design easiest and simplest to implement. In many cases, a well-prepared PNG can save many lines of code.
Can't agree enough with Slicy. It has saved me hours of time and headaches, as well as my designer. I think it's the kind of tool that has to fit your workflow, but if it does, absolutely worth it.
I've found that Skala Preview is also a very solid app for live previewing. Somewhat different to others, it integrates with Photoshop for live retina previews. I've no association, its just a great app.
Absolutely agree with the last point. While I wouldn't expect a designer to throw down much Objective-C quickly, the "move this element 5 points to the right" game can be played by a designer.
Add 5 minutes of guidance from a developer and some forethought (subclasses for common button idioms in your app and how to apply them to elements; storyboard overview; a hand from a developer to hook up a table view cell nib, etc) could save the developers a lot of time. Even gawds, understanding the naming conventions around assets.
My designer works in indesign, designs for 1x and scales up. As long as you know that images are 50%, it's much faster then doing everything in even pixels.
I can't imagine how app design in InDesign should work. Yes, InDesign has some effects, but they are not the same quality and power as PhotoShop's, and overall many of the tools lack pixel-precision that is needed.
Sure, it can work 90% of the way, but I'd recommend designing only in PhotoShop - it is the tool, best optimised for that.
PS is really heavy. It's powerful, but cumbersome for app design. Indd is way faster if you're designing up flows. You can change a color universally, embed things in different files in one command, you can set styles for type so every header, subhead, paragraph, etc, is the same, and you can change that all at once across all you files/design. And if you make a style guide, it's a lot faster.
I'm just an amateur, but I like to design as much as possible in vector graphics (I use inkscape) and then switch to bitmap (gimp for me, photoshop for most I guess) for the finishing touches. Makes it so much easier to scale stuff.
- He's very right about previewing on the device. I like xScope better than Silkscreen, because it can stream anything, both file, or screen region, and overall it's a nice designer's utility belt. There's nothing like that for android, at least I haven't found anything that works, and Android needs this even more, because it usually uses OLED, not LED screens.
- Unless you have plenty of time and very little UI, you shouldn't optimise for @1x design. The key is to design @2x assets that are ALWAYS even. Everything has to be 2 pixels or even-sized, every line, button size, coordinate and so on. To achieve crisp, 1px lines on Retina, you can do 1px strokes (for example, on button), but you have to make sure they are inside evenly sized (round-)rect, and twice as "strong" (darker, lighter, etc.), so that when PhotoShop resizes that 1px line, its darkness is mixed with the next pixel inside the button, and looks right on standard resolution.
- Another app I highly recommend: Slicy. Saved me many hours of work, and can automate the whole process of exporting assets.
- Keep the asset naming consistent, that will make developers happier and more productive.
- Learn at least the basics of iOS and Android app development. Basics are easy, and you will learn how developers layout the interfaces. That will get you thinking while designing, what assets will allow developers to make the design easiest and simplest to implement. In many cases, a well-prepared PNG can save many lines of code.