android keyboard height bug fix, density incorrect

In testing with galaxy s2, the keyboard height was not being calculated correctly.  I found out the density was being set to an int.  

From here..
http://stackoverflow.com/questions/3166501/getting-the-screen-density-programmatically-in-android

Density can be .75, 1, 1.5, 2, ect. thus it was being rounded to the nearest integer and causing the incorrect keyboard height.

I switched it to be a float
remove float cast
calculate dp's not device px