最近用到了Android flag的机制，把Android现在所有的flag列出来，供参考。
FLAG_GRANT_READ_URI_PERMISSION 0x00000001
FLAG_GRANT_WRITE_URI_PERMISSION 0x00000002
FLAG_FROM_BACKGROUND 0x00000004
FLAG_DEBUG_LOG_RESOLUTION 0x00000008
FLAG_EXCLUDE_STOPPED_PACKAGES 0x00000010
FLAG_INCLUDE_STOPPED_PACKAGES 0x00000020
FLAG_GRANT_PERSISTABLE_URI_PERMISSION 0x00000040
FLAG_GRANT_PREFIX_URI_PERMISSION 0x00000080
自定义 0x00000x00
自定义 0x00001000
FLAG_ACTIVITY_RETAIN_IN_RECENTS 0x00002000
FLAG_ACTIVITY_TASK_ON_HOME 0x00004000
FLAG_ACTIVITY_CLEAR_TASK 0x00008000
FLAG_ACTIVITY_NO_ANIMATION 0x00010000
FLAG_ACTIVITY_REORDER_TO_FRONT 0x00020000
FLAG_ACTIVITY_NO_USER_ACTION 0x00040000
FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET 0x00080000
FLAG_ACTIVITY_NEW_DOCUMENT 0x00080000
FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY 0x00100000
FLAG_ACTIVITY_RESET_TASK_IF_NEEDED 0x00200000
FLAG_ACTIVITY_BROUGHT_TO_FRONT 0x00400000
FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS 0x00800000
FLAG_ACTIVITY_PREVIOUS_IS_TOP 0x01000000
FLAG_ACTIVITY_FORWARD_RESULT 0x02000000
FLAG_ACTIVITY_CLEAR_TOP 0x04000000
FLAG_ACTIVITY_MULTIPLE_TASK 0x08000000
FLAG_RECEIVER_NO_ABORT 0x08000000
FLAG_RECEIVER_FOREGROUND 0x10000000
FLAG_ACTIVITY_NEW_TASK 0x10000000
FLAG_RECEIVER_REPLACE_PENDING 0x20000000
FLAG_ACTIVITY_SINGLE_TOP 0x20000000
FLAG_RECEIVER_REGISTERED_ONLY 0x40000000
FLAG_ACTIVITY_NO_HISTORY 0x40000000