What is the difference between enter/exit and popEnter/popExit animations?
Let's start simple case:
Replace Fragment A with Fragment B (your second code snippet)
- Fragment B runs enter animation
- Fragment A runs exit animation
Press back button and undo the replace operation
- Fragment B runs popExit animation
- Fragment A runs popEnter animation
Now to answer your question.
You don't say if the container already has a fragment or not. Let's consider both cases:
Container already had a fragment (let's call it Fragment 0) when the first operation to replace with Fragment A was called. When popping the entire stack:
- Fragment B runs popExit animation (set in second snippet)
- Fragment 0 runs popEnter animation (set in first snippet)
Container was empty so replacing with Fragment A was essentially an add operation. When popping entire stack:
- Fragment B runs popExit animation (set in second snippet)
- No popEnter animation runs since container is now empty