[4] Failed to install the app.

error Failed to install the app. Make sure you have the Android development environment set up: https://facebook.github.io/react-native/docs/getting-started.html#android-develop

Please set the JAVA_HOME variable in your environment to match the
location of your Java installation.

해결 방법

참고: stackoverflow

echo export "JAVA_HOME=$(/usr/libexec/java_home)" >> ~/.bash_profile
source ~/.bash_profile
npm run android

해결 방법

참고: stackoverflow

1. cd android && ./gradlew clean
2. chmod +x gradlew
3. npm run android