I have a question about the error that occurs when creating a dialog window using Android Activity theme!

Hello, I'm a student studying Android. I'm just going to use activity theme to create a dialog window. However, even if I tried googling and incorporated the methods found in googling, I couldn't figure out where the error came from, so I asked you a question ㅠ<

The picture above is an Android studio error message.

The picture above is the code for the activity class that will create the dialog window. The picture above is the contents of the manifest code.

The picture above is a code using int to move on to dialog activity when a click event occurs.

Thank you!