C172 Pilot reported having to take evasive action to avoid a collision with another aircraft while entering the pattern.

Narrative

The Bonanza pilot was on an extend downwind approach into ZZZ that seemingly started far south. Typically this is no big deal as the sky is big in the state but in this case my C172 came within 30 yards of colliding in the classic low wing; I didn't see the other guy as I descended into the airport environment; scenario.I was just coming out of a 270 degree sight seeing turn over the shipyard at 1;500 feet when I heard an alert from my ASPEN 1000 PFD (via headset) I've never heard the before... take immediate action. I took action and looked up an saw Aircraft Y. Evasive action was absolutely required and I learned a very important lesson about my ADS-B antenna. It has blind spots and I do not what to be close enough to see what the other pilot is wearing ever again.Aircraft Y track shows no sign of maneuvering and I'm curious if the pilot of Aircraft Y had any idea a collision was avoided?My takeaways: 'The preferred method for entering from the downwind leg side of the pattern is to approach the pattern on a course 45° to the downwind leg and join the pattern at midfield.' As per the FAA. I routinely do this or fly practice instrument approaches. It would seem that putting planes in predictable areas of the sky near airports has more merit than I once thought. Flying in this state has dulled my paranoia of collision which I need to rethink. Had the other pilot used the 45 degree entry into the pattern rather than a 50+ mile downwind entry he would not have been descending over the shipyard.