经过一些研究，我想我已经达到了我想要的。借助于这个https://stackoverflow.com/a/17246390/1463357还有这个https://stackoverflow.com/a/18213259/1463357波斯特：我能修好我的gradle。生成文件。

我的原始构建文件有两个问题。第一个问题是错误地定义了口味的依赖关系。依赖项必须在productFlavors之后定义，并且必须以flavorNameCompile的形式定义，如下所示：

productFlavors {
    free {
    }
}

dependencies {
    compile fileTree(dir: 'src/main/libs', include: '*.jar')
    freeCompile fileTree(dir: 'src/free/libs', include: '*.jar')
}

第二个问题是错误的源集定义。要正确定义口味的来源集，必须在来源集之前定义口味。像这样：

productFlavors {
    free {                
    }
}

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

应用这些变化后，不同口味的apk大小与预期不同，并且没有发现广告库的痕迹。

这是我最后的gradle.build文件：

buildscript {
    repositories {
        mavenCentral()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:0.6.+'
    }
}

apply plugin: 'android'

repositories {
    mavenCentral()
    mavenLocal()
}

android {
    compileSdkVersion 18

    buildToolsVersion "18.0.1"

    defaultConfig {
        versionCode 26
        versionName "2.0"
        minSdkVersion 9
        targetSdkVersion 18
        packageName 'com.example.myproject'
    }

    signingConfigs {
        debug {
            storeFile file("your path")
        }

        release {
            storeFile file("your path")
            storePassword ""
            keyAlias ""
            keyPassword ""
        }
    }

    buildTypes {
        debug {
            packageNameSuffix '.debug'
            versionNameSuffix '-DEBUG'
            signingConfig signingConfigs.debug
        }
        release {
            signingConfig signingConfigs.release
        }
    }

    flavorGroups 'market', 'version'

    productFlavors {
        google {
            flavorGroup 'market'
        }
        amazon {
            flavorGroup 'market'
        }
        slideme {
            flavorGroup 'market'
        }
        free {
            flavorGroup   "version"
        }
        paid {
            flavorGroup   "version"
            packageName = android.defaultConfig.packageName + ".paid"
        }
    }

    sourceSets {
        main {
            manifest.srcFile 'src/main/AndroidManifest.xml'
            java.srcDirs = ['src/main/java']
            res.srcDirs = ['src/main/res']
            assets.srcDirs = ['src/main/assets']
        }
        amazon {
            assets.srcDirs = ['src/amazon/assets']
            res.srcDirs = ['src/amazon/res']
            java.srcDirs = ['src/amazon/java']
        }
        slideme {
            assets.srcDirs = ['src/slideme/assets']
            res.srcDirs = ['src/slideme/res']
            java.srcDirs = ['src/slideme/java']
        }
        free {
            manifest.srcFile 'src/free/AndroidManifest.xml'
            assets.srcDirs = ['src/free/assets']
            res.srcDirs = ['src/free/res']
            java.srcDirs = ['src/free/java']
        }
        paid {
            assets.srcDirs = ['src/paid/assets']
            res.srcDirs = ['src/paid/res']
            java.srcDirs = ['src/paid/java']
        }
    }
}

dependencies {
    compile fileTree(dir: 'src/main/libs', include: '*.jar')
    compile 'com.android.support:support-v4:18.0.+'
    compile 'com.android.support:appcompat-v7:18.0.+'
    freeCompile fileTree(dir: 'src/free/libs', include: '*.jar')
}