What are my options?
There are many ways to notify users in your app, but some methods are more intrusive than others and you need to make sure that you don't disrupt the flow of your app.
If your app is highlighting an important, time-critical event, then your notification should be intrusive. But if you are just reminding users of an option or mentioning an update, you should try to be subtle.
Be subtle with a splat ...

Give the user a sneak peek ...

Be clear with a flashing LED ...

Make sure they get the message ...

- Dialog boxes, prompts, and toasts
- Check out the Cascades Dialogs sample app
- Check out the core Dialogs sample app
Be careful ...
Notifications should be used in combination with push notifications implemented using the Push Service, or when your app is running as a headless app in the background.
In addition to playing audible notifications for your app, a headless app can add notifications to the BlackBerry Hub for events that don't need immediate attention or display an instant preview for events that need the user's attention.
If a user receives a lot of notifications throughout the day, their phone uses more battery. Some notifications (for example, vibrations) use more battery than others, such as the LED. You should always use care when creating notifications in your app.
Users have many options to customize their notifications. Users can set persistent global notification settings and policies that impact all applications. They can also customize notification settings for each app on their device.
The notification system uses the combination of both of these settings to decide which effects actually get presented. When you are coding your app, you can set an application's default notification settings only once and only if the user has granted permission to your app.