Safely remove an Android Activity

I found my answer. To remove an activity, let the name of the activity is activity:

1. Remove the activity.java file from src folder (java/your.package.name folder for AndroidStudio)
2. Remove the activity.xml file from layouts folder (layout folder for AndroidStudio)
3. Remove the activity.xml file from res/menu folder (this is an optional folder)
4. Remove the <activity></activity> block of the activity from the manifest file
5. If the <activity> block in the manifest file has a reference (usually in android:label tag) remove the referenced value (usually from values/strings.xml).

According to answers from @ojonugwa ochalifu and @Md Tarik Mahmud you should also right click on app folder then Refractor -> Remove Unused Resources

Just do it in a two steps in Android Studio.

1. Delete the Activity's Java file: YourActivity.java
2. Select app from the Project-Browser in Left Panel. Click Refactor from menu, click Remove Unused Resources.

You are done.

I don't think there is any procedure to delete an activity at once from everywhere.

Delete the entry from manifest first. Then delete the Activity class file. Once class file is deleted you will start getting errors where it is used. Look into each error separately and resolve them.