Android-Studio upgraded from 0.1.9 to 0.2.0 causing gradle build errors now

Solution for me without reinstalling or creating a new project:

Step 1: Change line in build.gradle from:

dependencies {
    classpath 'com.android.tools.build:gradle:0.4'
}

to

dependencies {
    classpath 'com.android.tools.build:gradle:0.5.+'
}

Note: for newer versions of gradle you may need to change it to 0.6.+ instead.

Step 2: In the <YourProject>.iml file, delete the entire<component name="FacetManager">[...]</component> tag.

Step 3 (Maybe not necessary): In the Android SDK manager, install (if not already installed) Android Support Repository under Extras.

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Info found here