|Re: 42S on iPod Touch: OFF function behavior (bug?)|
Message #17 Posted by Thomas Okken on 10 Nov 2009, 12:42 a.m.,
in response to message #1 by Andrés C. Rodríguez (Argentina)
Handling OFF, whether the Shift-EXIT key sequence or the XEQ "OFF" command, is a tricky issue in an HP-42S simulator!
In Free42 for Windows, Linux, Mac, and Pocket PC, OFF simply exits the application. In Free42 for PalmOS, it turns the device off, but doesn't exit the simulator, so that when you turn it back on, you're still in Free42.
On the iPhone, the situation is a bit difficult, since iPhone applications aren't supposed to exit on their own initiative, and they also aren't able to turn the device off... so what *should* OFF do then?
Byron Foster's approach in his 42s port of Free42 is to bring up the "Options" screen instead. That seems like an excellent choice to me, but of course it's not going to work so well if you're running a program that executes OFF, or if you're used to pressing Shift-EXIT to shut down the simulator.
In my own Free42 for the iPhone, OFF exits the simulator, in flagrant defiance of iPhone user interface guidelines. I'm already steeling myself for the complaints from people that are used to Byron's 42s and expect the Options screen to come up instead. :-)
I guess both 42s and Free42 should have a setting that allows users to decide how they want OFF to behave. In a perfect world, the available options would include all of: (1) turn off the device, (2) exit the simulator and return to the home screen, and (3) bring up the Options screen.