How to get straight distance between two location in android?

Question

First read Question carefully ...

I need straight distance, not by walking,car,or etc.

Take a look to this image which given below,

Google provide us distance by car and driving.

But I don't want it, I want straight distance between two location (latitude - longitude).

Which is displayed as as RED LINE.

NOTE : I don't want to put red line on Google map, just want the Distance in Units(mile,km,etc.)

Answer 1

a = distance in degrees //meterConversion = 1609;

b = 90 - latitude of point 1

c = 90 - latitude of point 2

l = longitude of point 1 - longitude of point 2

Cos(a) = Cos(b)Cos(c) + Sin(b)Sin(c)Sin(l)

d = circumference of Earth * a / 360 // circumference of Earth = 3958.7558657440545D km