Abstract: A system and method are described for location-based and group-based operations on a data processing device. For example, a computer-implemented method according to one embodiment of the invention comprises: establishing a buddy group containing identities of a plurality of users within the group and notification data indicating when other users are to be notified about current locations of the users in the group; determining whether wireless data processing devices of two or more users of the buddy group are at the same location or within a particular distance of the location; identifying the users and the location; and notifying other users in the group of the identity of the users and the location.

Abstract: Timeline control techniques are described. In one or more implementations, a timeline is displayed that is divided into a plurality of intervals, each of which corresponds to a respective period of time. Responsive to selection of one of the plurality of intervals, a control is displayed within the selected interval that is scrollable within an area defined by the selected interval to move between content that is associated at corresponding points in time at a scrolling speed that is based at least in part on an amount of the content that is associated with the interval.

Abstract: A graphical user interface which employs logical barriers for temporarily preventing cursor movement between graphical elements under certain circumstances.

Abstract: Adjusting the GPS fix frequency of a wireless device is described. For example, a computer-implemented method according to one embodiment comprises: attempting GPS fix operations on a wireless device according to a first schedule; detecting one or more unsuccessful GPS fix operations; determining whether a location identified by a previous successful GPS fix operation is at or within a specified range from a first specified location; if the location identified by the previous successful GPS fix operation is at or within a specified range from a first specified location, then adjusting the wireless device to perform GPS fix operations according to a second schedule; and if the location identified by the previous successful GPS fix operation is not at or within a specified range from a first specified location, then adjusting the wireless device to perform GPS fix operations according to a third schedule.

Abstract: A computer-implemented system and method for navigating through a plurality of graphical elements with a trackball. For example, a method according to one embodiment of the invention comprises: detecting a substantially vertical motion on the trackball when a first element is selected; and responsively selecting either (a) a second element which is closest vertically to the first element or (b) a third element in the same horizontal line as the first element if a leftmost horizontal coordinate of the third element is closer to a leftmost horizontal coordinate of the first element than then leftmost horizontal coordinate of the second element.

Abstract: A graphical user interface which employs logical barriers for temporarily preventing cursor movement between graphical elements under certain circumstances.

Abstract: A computer-implemented system and method for navigating through a plurality of graphical elements with a trackball. For example, a method according to one embodiment of the invention comprises: detecting a substantially vertical motion on the trackball when a first element is selected; and responsively selecting either (a) a second element which is closest vertically to the first element or (b) a third element in the same horizontal line as the first element if a leftmost horizontal coordinate of the third element is closer to a leftmost horizontal coordinate of the first element than then leftmost horizontal coordinate of the second element.