Palm webOS: Developing Applications in Javascript Using the Palm Mojo Framework – Page 4
Banner notifications are displayed in a slow crawl along the bottom of the screen within the Notification bar, which sits just below the application window in what is called negative space since it is outside of the card’s window. After being displayed, banner notifications can selectively leave a summary icon in the Notification bar as a reminder to the user. Figure 1-6 shows an example of a banner notification and the summary icons are shown in Figure 1-7 indicating that the music player is active and that there is an upcoming calendar event and new messages.
At any time, the user can tap the Notification bar, which brings up the dashboard, shown in Figure 1-8. Notifications that are not cleared will display their current status within a dashboard panel.
Dashboard panels though are more than just summaries of notifications but are dynamic views enabling any background application to display ambient information or status. For example, the calendar application always displays the next event on the calendar even before the event notification has been issued. In Figure 1-8, the Music application shows the current song along with playback controls that you can manipulate to pause the music or change the selection.
The Notification Bar and Dashboard manage interruptions and events, keeping you abreast of changes in information without disrupting your current activities. It may help to think of them as an event-driven model for viewing and managing your world, while the Card view provides you with task-oriented navigation tools. The combination gives you a few powerful tools from which you can quickly track and access what you need when you need it.
Headless applications are those that can be completely served through the dashboard, as their entire purpose is to monitor and present information. For example, a weather application could display the current weather for a targeted location in a dashboard without having a card view at all.
You will tend to use the Card view to switch between tasks, launch applications and otherwise perform activities. Dashboard is used to monitor your world, to see what’s changed or what events have taken place, which will often drive new activities.