Incorrectly show/allow a pic when no activity is active/started

[tingsu]

• I have searched the history bug list, and have not found a similar bug.

• The bug was found on the latest version 1.4.0 (also on the master branch). The bug can be reproduced on an Android emulator 6.0 and a Google Pixel 3 XL phone.

• Bug description

  When no activity is active (i.e., <No Activity> is shown on the top), if the user tries to take a picture, he/she cannot load the picture. This is a correct functionality because no activity is started. In other words, it makes senses to disallow or avoid showing a picture to be taken for an "\<No Activity>".

  However, if the user selects an activity, e.g., Cinema and directly undo it. Then, he/she can successfully load a picture for <No Activity>. This is an obviously incorrect/inconsistent functionality.

• Video of correct functionality

• Video of incorrect functionality

[ramack]

definitely an issue and probably linked to #286, as the UNDO seems to mess up the current state.