Get the DPI size to use based on Screen Density and the Pixel size. This allows for calculation of image width and image height based on the pixel width and pixel height. Pass in the pixel size and it returns the dpi size to be used in Layouts.

pixel2dpi.java

  /**
	 * Takes a value in pixels and converts it to a dpi value.  It adjusts
	 * the dpi size based on the screen density that is returned by 
	 * android.
	 * 
	 * @param originalHeight
	 * @param context The activity context
	 * @return
	 */
	public static int getDPI(int pixelsize, Activity context) {
		DisplayMetrics metrics = new DisplayMetrics();
		context.getWindowManager().getDefaultDisplay().getMetrics(metrics);
		float sizeMultiplier = 1;
		switch (metrics.densityDpi) {
		case DisplayMetrics.DENSITY_LOW: {
			break;
		}
		case DisplayMetrics.DENSITY_MEDIUM: {
			break;
		}
		case DisplayMetrics.DENSITY_TV: {
			sizeMultiplier = 1.5f;
			break;
		}
		case DisplayMetrics.DENSITY_XHIGH: {
			sizeMultiplier = 3;
			break;
		}
		default: {
			sizeMultiplier = 3;
			break;
		}
		}
		
		int dpi = Math.round((pixelsize * sizeMultiplier) / metrics.density);
		return dpi;
	}