Revert "Revert "Revert "add function getActivityManager"""

This reverts commit f3fa0b1e8323ddd5a251299f452f7feacd178bae.
Revert "Revert "Revert "Revert "add function getActivityManager""""

This reverts commit 5b000fa216c6a4fa379d9b98d997ed26eec7b049.