PA28 Single pilot reported a NMAC with another aircraft passing perpendicular to the pilot's flight path.

Narrative

I was the only one on the plane returning from practicing basic maneuvers. I was not doing any maneuvers at the time of occurrence. Flying east at about 2500 ft. returning to ZZZ; about 10 miles away (guessing) on what would probably be a 275 radial. About that time I think I was notifying the Tower that I was inbound (not sure). Had been following traffic on my iPad previously. Looked forward and noticed a red and white aircraft (small single engine) going south to north at the same altitude not too far away. While the weather was supposed to be clear 10 miles plus; there seemed to be a haze at the levels I was flying possibly reducing visibility. Also; sunlight glare from the east. After returning home; I paced out 500 ft. and tried to remember how close the plane crossed in front of me. I'm not sure but it could have been anywhere from 300 to 700 ft. or more. iPad was not blue-toothed to my headphones. I plan to make sure that is active for now on for traffic warnings. I had been following it visually on flights where it showed ADSB traffic. I don't know if there was a warning from my iPad or not possibly because of planning arrival; getting weather and communicating with ZZZ. However; I'm not sure of the exact sequence of events.