如何将分辨率转换为dpi

Question

I did my analysis and found that most of the users of my application will be of samsung galaxy S2, and samsung galaxy note . Doing research on their technical spec, I found: Galaxy S2: 480 x 800 pixels, 4.3' display

Galaxy Note: 1280 x 800, 5.3”screen

How can I categorize these into Layout size and desnity level? I think I can figure out the layout size as mentioned in the android development page However I am unable to know the density level (low, medium high xhigh). They say that I need the dpi but in functional spec, I rarely see the dpi, I just see the above resolution Thank you

Answer 1

Calculate the density first Density=Square root((wp*wp)+(hp*hp))/di

where wp is width resolution in pixels, hp is height resolution in pixels and di is diagonal size in inches. It would come ~208 for S2.

ldpi ~120dpi,mdpi ~160dpi, hdpi~240dpi, xhdpi ~320dpi . Compare from these values of dpi

Answer 2

Not sure if I understand you correctly but you can request the density level and the dpi from the DisplayMetrics class. Using resolution and density you can approximate the display's size.

DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);