The approach used by me for renaming the package name is simple as follows:-

Step 1 : Select the Project option from left menu of Android Studio

Step 2 : Right click on java and add a new package and set the desired package name

Step 3 : Enter you new packagename

Step 4 :Copy all the files from your old package and paste in the new package

Step 5 :Rename the package name in manifest file

Step 6 :Rename the package name in build.gradle file

Step 7 :Then right click the old package and delete it with all its data, and delete that directory as well

Step 8 :Then Rebuild your project

Step 9 :Then you will find some errors of old import packagename in your project Select the old package name in any file and press CTRL + Shift + R , and enter you new package name in replace box, then press find

Step 10 :Then a popup appears like below and select All files option from it

Step 11 :Rebuild your project again, bingo your project packagename has been changed :)