TaskStackBuilder

Utility class for constructing synthetic back stacks for cross-task navigation on Android 3.0 and newer.

In API level 11 (Android 3.0/Honeycomb) the recommended conventions for app navigation using the back key changed. The back key's behavior is local to the current task and does not capture navigation across different tasks. Navigating across tasks and easily reaching the previous task is accomplished through the "recents" UI, accessible through the software-provided Recents key on the navigation or system bar. On devices with the older hardware button configuration the recents UI can be accessed with a long press on the Home key.

When crossing from one task stack to another post-Android 3.0, the application should synthesize a back stack/history for the new task so that the user may navigate out of the new task and back to the Launcher by repeated presses of the back key. Back key presses should not navigate across task stacks.

TaskStackBuilder provides a backward-compatible way to obey the correct conventions around cross-task navigation on the device's version of the platform. On devices running Android 3.0 or newer, calls to the startActivities method or sending the PendingIntent generated by getPendingIntent will construct the synthetic back stack as prescribed. On devices running older versions of the platform, these same calls will invoke the topmost activity in the supplied stack, ignoring the rest of the synthetic stack and allowing the back key to navigate back to the previous task.

### About Navigation For more detailed information about tasks, the back stack, and navigation design guidelines, please read from the developer guide and from the design guide.