How to schedule an alarm

Android provides AlarmManager to create and schedule alarms. Alarms offer the following features:

• Schedule alarms for a set time or interval
• Maintained by the OS, not your application, so alarms are triggered even if your application is not running, or the device is asleep
• Can be used to trigger periodic tasks (such as an hourly news update), even if your application is not running
• Your app does not use resources (such as timers or background services), since the OS manages the scheduling

Alarms are not the best solution if you need a simple delay while your application is running, for example, a short delay for a UI event. For short delays, it's easier and more efficient to use a Handler, as we've done in several previous recipes.

When using alarms, keep these best practices in mind:

• Use as infrequent alarm timing as possible
• Avoid waking up the device
• Use as imprecise timing as possible—the more precise the timing, the more resources required
• Avoid setting...