How to choose correct image resolution for android

Question

I have been battling with this for a couple of days. I am trying to write a small custom rating bar. With some custom images. When I check the image I have on my HTC Desire, the image looks horribly aliased. I have tried using different resolutions and different sizes and still can't figure out what resolution/how to create a good quality.

I have read the guidelines on the android site but, to no avail. I think the problem I am having is displaying lower resolution images on a higher dpi display. So the system upscales the image. But I am not sure how to fix that. Higher resolution images? Larger images?

Any advice would be great.

Alex

Answer 1

The reason why this is a bit of a challenge to get right is the wide variety of screen-resolutions and -densities of Android devices. Fortunately the Android SDK has pretty extensive support in this department. A very good start is this section of the Android Dev Guide.

Basically you need to understand the concept of Density-independent pixels (dp) and use classes like DisplayMetrics to calculate actual screen pixels. And yes, obviously you'll need larger, higher resolution images for higher density screens.