导入Facebook SDK Android Studio 0.8.14

Question

我导入Facebook SDK我的Android Studio。但是我遇到了像

这样的问题

Error:(12, 0) Could not find property 'ANDROID_BUILD_MIN_SDK_VERSION' on project ':FriendPickerSample'

这是我的facebook-android-sdk-3.20-0 / samples / FriendPickerSimple / build.gradle

apply plugin: 'com.android.application'

dependencies {
compile project(':facebook')
}

android {
compileSdkVersion 19
buildToolsVersion "19"

defaultConfig {
    minSdkVersion Integer.parseInt(project.ANDROID_BUILD_MIN_SDK_VERSION)
    targetSdkVersion Integer.parseInt(project.ANDROID_BUILD_TARGET_SDK_VERSION)
}

lintOptions {
    abortOnError false
}

sourceSets {
    main {
        manifest.srcFile 'AndroidManifest.xml'
        java.srcDirs = ['src']
        res.srcDirs = ['res']
    }
}

}

我该如何解决这个问题？