Additional System Services

Using Additional System Services

Using Alerts and Alarms

17

This section describes the use of functions and methods that provide alerts and
alarms, and the

protoPeriodicAlarmEditor

.

Using the Notify Method to Display User Alerts

17

The

Notify

method offers a simple way to display a message to the user. This

method takes three arguments. The first specifies which type of alert is displayed;
some alerts beep, some only log their notice instead of displaying it, and so on. The
other two arguments are strings shown to the user in the alert.

The following code fragment creates the slip shown in Figure 17-7:

:Notify(kNotifyAlert,"LlamaCalc",

"You've run out of Llamas!");

A user alert

Creating Alarms

17

The

AddAlarm

and

AddAlarmInSeconds

functions are used to schedule a new

alarm. You can also use these functions to substitute a new alarm for one that is
currently scheduled but has not yet executed.

The

AddAlarm

function creates each new alarm as a soup entry (thus, alarms

persist across restarts) and returns an alarm key that uniquely identifies the new
alarm. This alarm key is a string you provide as one of the arguments to the
function that creates the alarm; it includes your developer signature as a suffix. For
example, a typical alarm key might be the string

"lunch:myApp:mySig"

or

something similar. Note that only the first 24 characters of an alarm key are
significant.

Do not manipulate the alarm soup or its entries directly. Use only
the interface described in this chapter to manipulate alarms.