Can't migrate project to Gradle in Android Studio

The project thinks it's still a non-Gradle based project; it's not the presence of the build.gradle file that makes it Gradle-based, but it's how the project was set up in the first place. You'll need to re-import your project to finish the conversion to Gradle.

First, though, it looks like you don't have a settings.gradle file; it looks like you need one. Since you've set up your project as a single-module project, then you can put the file in your project's root directory, next to build.gradle. It should contain this:

import ':'

In the future if you add more modules to your project you may want to convert it to a multi-module directory structure, but you don't need to worry about that now. In any event, now you need to do the re-import in Android Studio:

1. Close your project
2. Back up your project
3. Delete the .idea folder in the root directory of the project
4. Delete all the .iml files in your project
5. Import your project in Android Studio, and in the dialog that prompts you for a file, choose the build.gradle file.

After this you should be good to go.

In my case, when I tried to open an existing gradle project and AS didn't recognize it like a gradle project, the problem was inside settings.gradle file. settings.gradle was corrupt because, for some reason, the semicolon was missing. The right structure is include ':app'; where app is the name of the project's module.

Also, if you need, you can put more than one module, like this: include ':module1', ':module2', ':module3';

I hope it could help someone.

In my case: Step 1: Project Structure > Settings.gradle (Open it and add-- include ':app'; .

Step 2: Goto Gradle Tab (It normally present in Left or Right of Android Studio) > Then click to Refresh All Gradle Project

Step 3: Bang....... I hope its work.(Its works for me)