I don't think it's recommended to update the local.properties
file to get to add the missing environment vars.
sdk can be installed on /Library/Android/sdk or /usr/local/ to be sure check it by
which sdkmanager
export ANDROID_HOME=$HOME/Library/Android/sdk
or
export ANDROID_HOME="/usr/local/share/android-sdk"
Then add it to the $PATH
export PATH=$ANDROID_HOME/tools:$PATH
export PATH=$ANDROID_HOME/platform-tools:$PATH
export PATH=$ANDROID_HOME/build-tools/28.0.1:$PATH
export ANT_HOME=/usr/local/opt/ant
export MAVEN_HOME=/usr/local/opt/maven
export GRADLE_HOME=/usr/local/opt/gradle
export ANDROID_HOME=/usr/local/share/android-sdk
export ANDROID_SDK_ROOT=/usr/local/share/android-sdk
export ANDROID_NDK_HOME=/usr/local/share/android-ndk
export INTEL_HAXM_HOME=/usr/local/Caskroom/intel-haxm
I used brew cask
to install Android SDK following these instructions.
More info see https://developer.android.com/studio/intro/update#sdk-manager