Tools/raw materials:
iPhone 12
IOS 12
Xcode2.03
1. Open Xcode software and check whether the current debugging tools are good. The device column shows that there are no external devices.
2. Connect an external device such as iPhone with a data cable, and a dialog box will pop up for you to confirm the device and proceed with the next operation.
3. After registering the certificate, displaying this page indicates that the installation is complete.
4. You can see a detailed list after connecting. At the same time, in the tab bar, click the external physical devices such as iPhone and iPad on the left. Simulator devices click on the right: all kinds of devices that can be tested, from iPhone 5 to iPhone 1 1, Apple Watch, Apple TV, etc.
5. I have connected to the iPhone, but I see a prompt: the OS version is lower than the deployment target, and the operating system version on the iPhone (iOS 12) is lower than the deployment target (iOS 13). In this case, you need to lower your deployment goals.
6. Just change the development information in Xcode-iOS in the target to be lower than (iOS 12).