Expo 未显示 React Native 应用程序的二维码

Question

Usually when I run npm start / expo start the expo CLI starts and I am able to scan the QR code using expo on my phone. However after I start the app a few times, the QR code no longer begins to show up and I can no longer scan it.

Bottom Lower Corner of the Expo Developer Tools which usually shows a QR code

NPM command prompt running without a QR code

Answer 1

For me, I also had an error at the top of the console:

Linking is disabled because the client scheme cannot be resolved

To resolve, I simply had to run this:

npx uri-scheme add [your app name]

It added the uri schemes and the app then showed the QR code.

source: this issue

Answer 2

I have faced the same issue when I updated the expo-cli with this command. npm install -g expo-cli

I have followed these steps and worked for me,

1. Stop your expo with command CTRL+C
2. Delete the node_modules folder in the project
3. Run command npm install
4. Run command npm start

I hope this would help you.