For those who want to use simpleUML in Android Studio and having issues in running SimpleUML.
First download simpleUML jar from here https://plugins.jetbrains.com/plugin/4946-simpleumlce
Now follow the below steps.
Step 1:
Click on File and go to Settings (File → Settings)
Step 2
Select Plugins from Left Panel and click Install plugin from disk
Step 3:
Locate the SimpleUML jar file and select it.
Step 4:
Now Restart Android Studio (File → Invalidate Caches/Restart → Just Restart)
Step 5:
After you restart Right Click the Package name and Select New Diagram or Add to simpleUML Diagram → New Diagram.
Step 6:
Set a file name and create UML file. I created with name NewDiagram
Step 7:
Now Right Click the Package name and Select the file you created. In my case it was NewDiagram
Step 8:
All files are stacked on top of one another. You can just drag and drop them and set a hierarchy.
Like this below, you can drag these classes