Phone: Prompt port number invalid when the port number length too long

The number format exception occurs if the length of the port
number is too long, but it does not catch this exception,
so the phone force closed.

Add the handle of number format exception, then show a alert dialog.

CRs-Fixed: 412220

Change-Id: I3c37e4d19ce6f50bb4820716c8d7533e43c7cfc9