In the file layout app/code/Mageoneplus/Rewardcredit/view/adminhtml/layout/rewardcredit_earningrules_index.xml, you can call a file ui component instead block [...]
Maybe you know that it needs to register a model in file config.xml in magento 1. Now, with magento 2, it will be easier more than. We only need to create two [...]