No, and i'd bet my last dime on this.
Look at the batcave! It was being re-built alongside the Wayne Manor re-development during TDK, and would have taken years to get it to the state it's in. Why would he keep building when he retired straight after TDK? 8 yrs is too long for him to disappear. What was Wayne doing for that time?
My educated guess is that after TDK he lay low for a while, but came back and was active for some years, chased by all sorts of agencies while trying to clean the city up. Then over time he phased himself out, and and at the start of TDK(assuming it is a chronological film, i.e- no flashbacks), he his in a state of retirement. If his limp is an injury from the end of TDK, then how does he recover from that during the course of ~TDKR? Nonsensical. I think his injury may be from a close encounter with the police, like a chase or something, and because he is past his physical peak, he get's messed up, and then retires...or maybe it happens before the film.
Here's why I don't think he's inactive that whole 8 years:
1. He
needs Batman. If there's nothing obvious for Batman to do, Bruce will find an excuse. Think about it... Batman has to enforce the whole Harvey Dent act... make sure the band-aid is on tight. My bet is Nolan's Batman
does have a "rogue's gallery" of sorts by TDKR, but it's made up mostly of petty criminals and crime bosses instead of the ones we're all familiar with.
2. The cane. We already know that the cane is
not a result of his first fight with Bane. I
refuse to believe that he's still on a cane
eight years after the encounter that killed Two-Face, because if so, then Bruce has always been
weak as hell and will
never heal from it. I believe the cane is a result of two things: a) a accumulation of injuries sustained starting with that fall at the end of TDK and then continuing through at least
part of that 8-year gap, and b) mental faculties and where Bruce's head is at that time. It's quite possible that the cane is more of a mental manifestation than anything, that he doesn't
actually need it, but clings to it almost like a security blanket.
So no, Batman is not
totally inactive during that eight-year gap. He might be inactive for the last two or three years, but I'm convinced that, during
most of that 8-year gap, Batman was active, even if in only a minor way.