Build
ionic cordova build --release android
generate keytool
keytool -genkey -v -keystore my-release-key.keystore -alias alias_name -keyalg RSA -keysize 2048 -validity 10000
sign the jar
jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore my-release-key.keystore HelloWorld-release- unsigned.apk alias_name
zipalign
zipalign -v 4 HelloWorld-release-unsigned.apk HelloWorld.apk