Status bar
（1）Bluetooth opening prompt
（2）WIFI Signal
（3）SIM card prompt window (the picture shows the state without SIM card inserted)
（4）Power display (charging status in the picture)
（5）Time display
（6）View background process
（7） Return to the main page
（8） Return to the previous step
①
②
③
④ ⑤
⑥
⑦
⑧
