F IGURE 5.3
The user requests to register its copy.
As an aside, one of the more characteristic challenges when writing MIDLets is the ability to
produce cross-device usable software, especially when it comes to screen management and
user interaction. Depending on the kind of device the MIDlet is running on, the screen size and
overall user interaction may change very much. Figure 5.4 shows the same communication as
Figure 5.3, but with the MIDlet running on a pager device.
F IGURE 5.4
The user types in the license data into a two-way pager.
Getting back to the MIDlet interaction, once the user filled in the registration form, the data is
sent (wirelessly or with other device-dependent type of connection) to a Web server, where it is
evaluated. If the license id and password are valid, a positive response is returned to the
MIDlet, and the message in Figure 5.5 is shown to the user.