Cordova Android build error "Cannot read property 'length' of undefined". An error occurred while running subprocess cordova.

My ionic project was working perfectly without error. But when I was trying to build the ionic project using the command "ionic cordova build android". I got the following error,

Cordova Android build error "Cannot read property 'length' of undefined"

To know more detail about the error I command "ionic cordova build android --verbose" then I come 

to know gradlepath value is undefined. I was already installed gradle in my PC. 

Then I checked the enviroment variables path value that also perfect. 

I downgrade cordova cli 

npm install -g cordova@6.4.0

I also removed platform folder and added using the command.

ionic cordova platform rm android

ionic cordova platform add android

after I run the build the project same error. I searched internet no solution

Solution:

Finaly I realised I was updated by Android studio 4.0.1 (windows). Previously I installed 3.0.1.

now I removed the recent one and installed the previously android studio.

Next, I closed the visual studion code and reopened it and opened my project and run build 

command. The project build succeful and apk was generated in output path.