RV-9 Pilot reported an NMAC occurred with another aircraft while in the traffic pattern and performed an evasive maneuver to avoid collision. The Reporter announced position and intentions while at different distances from the airport and did not hear the other pilot announce anything on the radio.

Narrative

I apologize if the form is filled out incorrectly. I was returning to ZZZ from a flight to ZZZ1 to drop off a friend because they were buying an airplane there. Upon returning to my home airport of ZZZ; I entered a left downwind on a 45-degree angle for Runway XX. When I entered the downwind; I was approximately 1 mile southeast of the airport. I straightened out my aircraft parallel to Runway XX-XY heading XXX at around 2200 ft. with approximately 1 mile of spacing between my plane and the runway. Within what felt like a split second; I caught a glimpse of a Cessna 177 approaching me from the front-right at approximately 2100 ft. I took evasive actions by turning sharp to the right and climbing but by the time I saw them; it would have been too late. Thankfully I was at the proper pattern altitude of 2200 ft. When I talked to them on the radio; they said that they did not know I was there until my plane cast a shadow over the cockpit. We were close enough that I could see the paint scheme; type of airplane; and tail number. Again; had I not been above them I believe we would have collided. When I was approaching the airport; I announced my position and intentions at 15 miles out; 10 miles out; 5 miles out; and 2 miles out. I also announced when I entered the downwind. They did not announce anything on the radio. Supposedly they just got off the radio with ZZZ Approach who should have warned them of traffic in the area. Either they did not do that; or they did not listen to their warning. Their ADS-B track showed them fly straight through the pattern at ZZZ and continue on. They were not joining the pattern nor had any intention of landing at ZZZ. I was able to gather myself and land safely without further incident.There are takeaways that I got from this. First; I want to check and make sure that my ADS-B Out is working correctly. I've already submitted for an ADS-B Out check from the FAA and will likely fly tonight or tomorrow and call the ZZZ Approach to verify that my ADS-B Out is working. If not; I will attempt to fix it immediately. Second; I am going to connect my headset to my iPad via bluetooth so that it will give me audible warnings when I am approaching other traffic. Had my iPad been connected to my bluetooth headset; I would've heard it call out the approaching traffic. I don't like staring at my iPad while flying and at the time I was experiencing moderate turbulence that made it near impossible to see the iPad anyway. An audible warning could have helped prevent this near miss. Thankfully nothing bad happened and the pilot of the other aircraft was apologetic on the radio about the situation. I am alive and there are many lessons to be learned from this incident.