BlackBerry Java Development Environment (BlackBerry JDE) 4.2 and later
On the BlackBerry device, a screen can either be shown within the user interface (UI) of the foreground application, or it can be shown as a global screen (which is shown regardless of which application is in the foreground). Global screens can be used to bring alerts, reminders, and other background services to the BlackBerry device user’s attention without the need for the calling application to be in the foreground. With global screens, only one may be displayed at a time (others are queued behind it based on priority). Third-party applications are restricted to setting the priority of their global screens to a maximum level, as outlined by the following priority list:
Incoming call screen
Device locked screen
Third-party application global screens
The most common use of a global screen is as a dialog box for a notification (as is done with calendar reminders). Previously, global screens were to be displayed and dismissed using the queueStatus() and dismissStatus() methods of the class net.rim.device.api.ui.UiApplication. These methods have since been deprecated and replaced by pushGlobalScreen() and popScreen(), which are also from the UiApplication class.
If an application is still using queueStatus() and dismissStatus() in order to accommodate older BlackBerry devices, they should not mix these calls with pushGlobalScreen() and popScreen(). That is, do not use queueStatus() to display a screen and then popScreen() to dismiss it. By the same token, pushGlobalScreen() and dismissStatus() should not be combined. Mixing these calls may result in an IllegalStateException due to updates to the UI framework in newer versions of BlackBerry Device Software.