We converted the KotlinTutorial project for Android Studio 3.3, and have found a problem when you first use it.

The problem happened now and then with earlier versions of Android Studio, but is now occurring consistently with version 3.3

Fortunately, it's very easy to fix.

After you've extracted the project from the zip file, in the resources for these videos, open it as normal in Android Studio.

You'll find that instead of the project name - KotlinTutorial - at the top of the Project pane, you'll see the path to the project.

To fix the problem, go into the File menu and choose Sync Project with Gradle Files.

That will fix the problem, and you'll see KotlinTutorial in the Project pane.

You'll still need to rebuild the project before it will run, as Tim describes in the video.

So after following along with Tim, to download and extract the project, remember to go into File > Sync Project with Gradle Files before attempting to run it.

UPDATE:

With Android Studio 3.5 and above, more students are having problems - especially on Windows.  If the steps above don't work for you, then download and install the Community Edition of IntelliJ IDEA.

Android Studio is a version of IntelliJ IDEA that's been configured to create Android apps.  That means you'll find both products are very similar to use.

If you want help installing IDEA, Tim has a video on his YouTube channel, at https://www.youtube.com/watch?v=cu9-chtteAg&list=PLXtTjtWmQhg0hJNYj8KtCESXfwM3ReGsG&index=6

If you follow that video, there's no need to set up the Java JDK for this course.  That's only needed for Java programming, and you can skip that step.

We tried to avoid students having to install another IDE, by hacking Android Studio's build files.

Our hack works for most students, especially on Linux and Mac. It's now causing problems for some students on Windows - the latest versions of Android Studio don't like the hacked build files.

If you can't get the KotlinTutorial project to work, installing the Community Edition of IntelliJ is a better option than spending hours trying to work out why.

Once you've installed IntelliJ, don't try to use the KotlinTutorial project. Instead, choose the option to Create New Project from the IntelliJ Welcome screen.

Select Kotlin on the left, and JVM | IDEA on the right, then click Next. Enter a name for the project, and click Finish.

You can then create new Kotlin files by expanding the project in the project pane, and right-clicking on src.