UdaciCards

The class project for the React Native section of Udacity’s React Nanodegree course.

UdaciCards is a basic flashcards/quiz app. You can create decks of flashcards, each card containing a question and answer. You can quiz yourself on a deck, noting how many answers you’ve gotten right.

This project was bootstrapped with Create React Native App.

Platforms

This app has only been tested on the iOS simulator.

Starting up

yarn install

yarn start

Troubleshooting

Networking

If you're unable to load your app on your phone due to a network timeout or a refused connection, a good first step is to verify that your phone and computer are on the same network and that they can reach each other. Create React Native App needs access to ports 19000 and 19001 so ensure that your network and firewall settings allow access from your device to your computer on both of these ports.

Try opening a web browser on your phone and opening the URL that the packager script prints, replacing exp:// with http://. So, for example, if underneath the QR code in your terminal you see:

exp://192.168.0.1:19000

Try opening Safari or Chrome on your phone and loading

http://192.168.0.1:19000

and

http://192.168.0.1:19001

If this works, but you're still unable to load your app by scanning the QR code, please open an issue on the Create React Native App repository with details about these steps and any other error messages you may have received.

If you're not able to load the http URL in your phone's web browser, try using the tethering/mobile hotspot feature on your phone (beware of data usage, though), connecting your computer to that WiFi network, and restarting the packager.

iOS Simulator won't open

If you're on a Mac, there are a few errors that users sometimes see when attempting to npm run ios:

"non-zero exit code: 107"
"You may need to install Xcode" but it is already installed
and others

There are a few steps you may want to take to troubleshoot these kinds of errors:

Make sure Xcode is installed and open it to accept the license agreement if it prompts you. You can install it from the Mac App Store.
Open Xcode's Preferences, the Locations tab, and make sure that the Command Line Tools menu option is set to something. Sometimes when the CLI tools are first installed by Homebrew this option is left blank, which can prevent Apple utilities from finding the simulator. Make sure to re-run npm/yarn run ios after doing so.
If that doesn't work, open the Simulator, and under the app menu select Reset Contents and Settings.... After that has finished, quit the Simulator, and re-run npm/yarn run ios.

QR Code does not scan

If you're not able to scan the QR code, make sure your phone's camera is focusing correctly, and also make sure that the contrast on the two colors in your terminal is high enough. For example, WebStorm's default themes may not have enough contrast for terminal QR codes to be scannable with the system barcode scanners that the Expo app uses.

If this causes problems for you, you may want to try changing your terminal's color theme to have more contrast, or running Create React Native App from a different terminal. You can also manually enter the URL printed by the packager script in the Expo app's search bar to load it manually.