How best to convey a message from one Fragment to its parent (onActivityResult equivalent)?

If your fragments are closely tied together, just don't run them in separate activities. For the single pane case you can just switch fragments within one activity.

IMHO, fragments should not load other fragments. Activities load fragments, based upon available screen space. Fragments should neither know nor care whether any other fragment exists in the current activity, or if other fragments are in other activities.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.