creating Android assets (LPDI,MDPI,HDPI,XHDPI) for an app?

Question

I Need to create a Designs for a Andriod Application.

I can see everyone are speaking about this "ldpi,mdpi,hdpi & xhdpi....etc.," My biggest doubt is in WHAT RESOLUTIONS, I should create the designs in Photoshop?? As there are lots of screen sizes available now. WHAT DEFAULT SCREEN SIZES I SHOULD DESIGN WITH FOR EACH "ldpi,mdpi,hdpi & xhdpi ?" Like for Xhdpi - What Screen resolution Should I do ?

a. 720x1280 - 320 dpi
b. 2048x1536 - 320 dpi
c. 2560x1536 - 320 dpi
d. 2560x1600 - 320 dpi

Again the same resolutions for ldpi,mdpi and hdpi ? What Screen Resolutions for the respective DPI's Which Screen Resolutions for

a. 120 dpi ?
b. 160 dpi ?
c. 240 dpi ?

PLEASE CLARIFY ME GUYS. THANKS A TON IN ADVANCE

Answer 1

See this calculator.

ldpi is 120 dpi
mdpi is 160 dpi
hdpi is 240 dpi
xhdpi is 320 dpi
xxhdpi is 480 dpi 
xxxhdpi is 640 dpi

(Thanks to Tobor for adding those last two and correcting my typo, I accidentally overwrote his edit)

Also, I don't know why Maneti's initial advice was downvoted. When in doubt, use this tool (or the one in your android sdk) to generate your icons, then import those icons you generated into Photoshop. That's actually the most pragmatic and easiest solution (that doesn't require any thinking on your part and yet that solution works all the time for densities).

As to the size of an image (as defined by the Android guidelines/terminology), only worry about the size of that image if it's a image that could potentially take the entire width, or the entire height, of the screen (like a large background image for instance).

So in most cases, most developers end up not needing the size qualifier for their drawables (because it won't make a difference unless it's a large background image).

Answer 2

For 120, 160, 240 dpi, respectively, I'm condidering 240*320, 320*480 and 480*800 (or 854) screen sizes.
For xhdpi (320) I'm considering 1280*720 (or 800).

But this is only a reference

Take in account that your design should scale

So, the graphical elements should stretch or be repositioned well.

After all, the screen size is not so important, if you project your objects positions and sizes well.

Use dp for objects and sp for font sizes, use the proper dpi resolutions for graphics and you shold be fine.

You can't follow any existing resolution. Generalize.

Answer 3

You could start with with XXHDPI and then export your assets from there. I found that 1080px x 1920px and 72ppi is a comfortable size to design in Photoshop and allows you to export to other resolutions by downscaling (you should avoid scaling assets up). You can then you use this Photoshop script I wrote or Cut&Slice me to export assets from that document to the other resolutions (XHDPI, HDPI, MDPI, and LDPI).

I would also recommend using a Sprite Sheet PSD for your assets to keep things clean and organized.

Hope this helps.

Answer 4

first I think you meant ppi not dpi.
second since the graphics are intended to be used on screen only the size in pixels matters. The ppi could be what ever you want.
ppi (pixels per inch)/dpi (dots per inch) is used to measure the resolution of the output in the real world.
So why people use ppi if it doesn't matter?
Some people like to use the ppi when sizing the files for proportions. This way you can change the ppi number and get the proportions right.
let's assume you start with xxhdpi with a ppi of 480.
Then if you change to 320 you will get xhdpi
240 > hdpi
160 > mdpi
120 > ldpi
but you can use percentages as well.