这年头都不懂看说明书的吗? User Guide 里写的清清楚楚的事情还要来开个帖子问是不是 bug ?都不调查一下就以为自己捡到大新闻了吗。。。
https://help.apple.com/iphone/11/#/iph6d162927aTo use Face ID, you must set up a passcode on your iPhone. You must enter your passcode for additional security validation when:
The device has just been turned on or restarted.
The device hasn ’ t been unlocked for more than 48 hours.
The passcode hasn ’ t been used to unlock the device in the last six and a half days and Face ID hasn ’ t unlocked the device in the last 4 hours.
The device has received a remote lock command.
After five unsuccessful attempts to match a face.
After initiating power off/Emergency SOS by pressing and holding either volume button and the side button simultaneously for 2 seconds.