Android App - Result from math calculation is not showing up on screen : I am attempting to make a simple android app that calculates the diameter of a sonar signal. The user inputs the depth(in meters) and angle(in degrees) and the app inputs the information into the formula: 
2.0 * depth * Math.tan(angle / 2.0)


So I have created the UI and the java code and when I go to run the app in a VM it loads, I enter numbers in to test it, and when I hit the calculate button it does nothing. I am new to java and android development in general so if anyone could shed some light that would be great. 

Here is the MainActivity.java: https://gist.github.com/enporter/5c6238d0d81afaa13de9f473cd327c87

XML file for the UI widgets activity_main.xml: 
https://gist.github.com/enporter/80bef3f89c2240838aab4a0472f42ba9

I suspect the problem is something to do with this code that includes the formula but I am not sure so any help would be greatly appreciated: 

                ```double depth1 = Integer.parseInt(depth.getText().toString());
                double angle1 = Integer.parseInt(angle.getText().toString());
               double result1 = 2.0 * depth1 * Math.tan(angle1 / 2.0);
                result.setText(valueOf(result1));```