backcourt---the most confusing rule in b-ball

[Ralph Stubenthal]

A1, in his backcourt, throws the ball to A2. With both feet on the floor, 1 in frontcourt and 1 in backcourt, he catches the ball. Is it backcourt when:
1) he lifts the foot in frontcourt and sets it down in backcourt?
2) he dribbles into backcourt?
3) he passes the ball to someone in backcourt?

I suppose what my question consists of is: when the player catches the ball while standing with one foot in front and the other in backcourt, has he established frontcourt possession?