Move the locking button to a floating action button (FAB)

[GrazianoCapelli]

At this time the lock button is on the top-left corner, near the 3 yellow angle values. Unfortunately in this position the button (that is the most used one) is not comfortable for the user.
We would like to move the lock button on a FAB (floating action button) located in the bottom-right corner, the standard position of the Android FABs.

Here a mockup of the main activity:

The button should work exactly like the existing one, using setOnTouchListener.
In the future we might use the angles label on top-left corner to copy the values to the clipboard (issue #5).

PS: the FAB it is NOT 100% standard: the implementation is a bit tricky because the activity doesn't rotate when the user rotate the phone; We rotate only part of the interface, without re-create the activity.

[dhfherna]

Hi, I would like to work in this issue!

[GrazianoCapelli]

Hi @dhfherna,
I want to point out that the FAB it is NOT 100% standard: the implementation is a bit tricky because the activity doesn't rotate when the user rotate the phone; We rotate only part of the interface, without re-create the activity.
I added the note to the header comment too.

If you are comfortable with this, give me the OK and I'll be glad to assign the issue to you.