It's more than just the trade war. Apple's China business has been under pressure for a while

Apple CEO Tim Cook blames a revenue guidance cut on Greater China's economic struggles — exacerbated by trade tensions, but the iPhone-maker has been facing other challenges too.

from World News & Analysis https://www.cnbc.com/2019/01/03/apples-china-business-was-under-pressure-even-before-the-trade-war.html