What does “Just Keep Swingin’” mean?

“Just Keep Swingin’”, is the best advice I have for you, in baseball and in life.

Things going good? Just Keep Swingin’.
Things going bad? Just Keep Swingin’.

4-4? Just Keep Swingin’.
0-4? Just Keep Swingin’.

Got a promotion at work? Just Keep Swingin’.
Got fired from your job? Just Keep Swingin’.

Celebrated 5 years in your relationship? Just Keep Swingin’.
BF or GF of 5 years dumped you? Just Keep Swingin’.

All-American? Just Keep Swingin’.
Cut from your high school team? Just Keep Swingin’.

You’re bound to hit the ball at some point.