Best way to delete Activity and its references in Android Studio

I don't think automatic references removal is possible, but you can use the safe delete feature (right click on the activity -> delete -> check the safe delete option) to find all references in code and comments. Anyway, if a reference points to non-existing class, your project won't compile and an error will be shown with detailed information, so you'll be able to solve it quickly.

If you are on windows press Ctrl+Shift+F or Command+Shift+F for Mac to open the Find in Path dialog and enter FooActivity. This should show you all occurrences of FooActivity.

I'm answering my own question since I figured out a way to see exactly what got added after creating a new activity.

Since I was putting everything under Git version control, I realized that I could do a git diff with a fake activity to see exactly what the changes were. I discovered that the following files are added whenever a new activity is created:

FooActivity.java
app/src/main/res/layout/activity_foo.xml
app/src/main/res/menu/foo.xml

In AndroidManifest.xml, the following is added:

<activity
    android:name=".FooActivity"
    android:label="@string/title_activity_foo" >
</activity>

In app/src/main/res/values/strings.xml, the following is added:

<string name="title_activity_foo">FooActivity</string>

Of course, this wouldn't catch other references that were added after creating the new activity, so EyesClear's and Shahzad's answers would allow you to find these references. But in the future, I would probably checkout a new branch before creating a new activity so that I could nuke any changes that I don't like.

I was working on deleting an Activity and found a way.

You can right click on an activity->Find Usages(Alt+F7).

You will get a list of files where the activity is used in the project, and then delete.