Use pk8 and x509.pem files in AOSP to generate the keystore file for Android Studio

genkeystore.sh

#!/usr/bin/bash

# generate the keystore and show the result
storepassword="password"
outkeystore="mygen.keystore"

if [ $# -gt 0 ]; then
    outkeystore="$1"
fi
if [ $# -gt 1 ];  then
    storepassword="$2"
fi
if [ -f "$outkeystore"  ] ; then
    echo "found exist keystore: $outkeystore"
    exit -1
fi

for keyname in "media" "releasekey" "shared" "platform"
do
    echo $keyname
    openssl pkcs8 -inform DER -nocrypt -in "$keyname.pk8" -out "$keyname.pem"
    openssl pkcs12 -export -in "$keyname.x509.pem" -inkey "$keyname.pem" -out "$keyname.p12" -password pass:android -name "$keyname"
    keytool -noprompt -importkeystore -deststorepass "$storepassword" -destkeystore "$outkeystore" -srckeystore "$keyname.p12" -srcstoretype PKCS12 -srcstorepass android
done
keytool -list -v -keystore "$outkeystore" -storepass "$storepassword" && echo "done"