Droid X is large screen ?

Question

Reading the documentation: http://developer.android.com/guide/practices/screens_support.html. I judged that Droid X is a large screen phone, since it's physical dimension is 4.3". But reading/exploring further I'm realizing that large modifier has little to do with screen size.

As there's quoted in documentation:

Note that the density and the screen size are independent parameters and are interpreted by the system individually. For example, WVGA high density is considered a normal screen because its physical size is about the same as one of T-Mobile G1. On the other hand, a WVGA medium density screen is considered a large screen — it offers the same resolution but at lower pixel density, meaning that it is both physically larger than the baseline screen and can display significantly more information than a normal screen size.

I'm confused, can anyone clarify.

Thanks.

Answer 1

Disclaimer: Not an Android/mobile developer.

I think it does have to do with physical screen size. The example is noting that of two WVGA screens with the same resolution, the one with the higher pixel density will necessarily be smaller since it's packing the pixels in tighter.

I think they're trying to give an indication of how to design your interface. Remember, most of us have used 640x480 resolutions on 15 inch monitors, but that doesn't make it a good idea to display the same data on a 4 inch screen. Similarly, even if you can pack 480x800 pixels onto a 1 inch screen doesn't mean it will be practical to have a virtual keyboard on it. Thumbs have physical restrictions, not resolution restrictions, as do eyes.

The difficult part for me is when they say "can display significantly more information". Resolution is often a factor there, not physical size alone, although, as I said, eyes do have limitations so physical size is important too.

Answer 2

It's mostly size, actually, though their method makes it seem more complicated. The Droid X is WVGA high-density (200-250 pixels/inch), even though it's a larger screen than the 3.7" Droid 2 with the same number of pixels. A 5"+ WVGA or higher device would be considered WVGA medium- or low-density (160 PPI or less) though, which would count as large-screen, since it would have fewer PPI.

But here's why it's not purely a physical screen size: a low-PPI 5" device would be limited on the display front, not the interactibility front. That is, you could have a manageably interactible iPad-style paneled view, but labels would become fuzzy and hard to read if it had a QVGA resolution, making it impractical. A 5" WVGA device, on the other hand, probably could qualify as "large" because it could provide legible tablet-style views and and still provide usable finger interactions.

It's a bit of a fuzzy definition, but I'd think (as a developer, at least) a good rule of thumb for what shuold get the "large" modifier might be "Can I cram a folder list panel view to the right side of my email inbox list and still use this device comfortably without squinting or hunting for a capacitive stylus?"

Answer 3

It seems Droid-X has NORMAL screen. I just created a dummy app that contains all the variations of screen-sizes and densities (9 combinations in total) and ran it in the DroidX emulator (you can obtain one from motorola dev site) and it loads normal-hdpi resource.