Canalys's latest report provides valuable information on the state of the Chinese smartphone market at the end of Q1 2018. Going by the data, the market saw a whopping 21% YoY drop in shipments, with companies like OPPO, Vivo, and Samsung all seeing dwindling sales numbers.
https://www.notebookcheck.net/China-woes-intensify-as-local-smartphone-market-sees-massive-21-decline-in-Q1-Xiaomi-overtakes-Apple-more.301356.0.html