I want the character to enter the overlap and display the UI, then select different buttons by clicking the mouse to transfer the character to the specified Tilemap。
I tried it myself for over ten hours, but the first problem was that the mouse couldn’t interact with the button at all. The second issue is that the mouse cannot click.
Are you sure you enabled mouse input? Mouse cursor you see may be from editor.
Watch some tutorial about umg and mouse input (it is just few nodes to enable mouse).
Or:
make HUD blueprint
in that bp print message that you clicked mouse
Then you know if mouse for game is enabled.
Or:
get inside button blueprint
add hoover over event and click event
print on booth when they happen
Because button will not work (will not receive events) if something else is covering it. Only most top widget gets clicked and mouse over events.