How to convert fahrenheit to celsius with a popupmenu

Hi guys, i need your help with something:

I need a program to convert celsius to fahrenheit

on my GUI i have 2 edittext and and 1 popupmenu and 3 buttoms

i have to insert 1 value on the edittext 1, select the value to convert with the popupmenu (in this case fahrenheit)

and when i do clic on the bottom calculate, the value in celsius should be print on the edittext 2.

I hope you guys can help me

[Rik]

What have you tried so far? Keep in mind that you have to convert the char array to a numeric value when retrieving the text from an edit field.