Gradle：项目取决于库，但本身不是库

Question

I have android solution that contains 3 projects:

• app . Presentation layer, that contains logic for UI. Android application project;
• domain . Business logic. Java library project;
• data . Data storage. Android library project;

App depends on domain. Domain depends on data.

Here is build.gradle of the app project:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 21
    buildToolsVersion "21.0.1"

    defaultConfig {
        applicationId "com.company.name"
        minSdkVersion 15
        targetSdkVersion 21
        versionCode 1
        versionName "1.0"
    }

    signingConfigs {
        debug {
            ...
        }
    }

    buildTypes {
        ...
    }
}

dependencies {
    compile project(':domain')
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.github.asne.facebook:facebook:3.17.2'
    compile 'com.google.android.gms:play-services:6.1.11'
    compile 'com.android.support:appcompat-v7:21.0.0'
}

build.gradle of the domain project:

apply plugin: 'java'


dependencies {
    compile project(':data')
}

build.gradle of the data project:

apply plugin: 'com.android.library'

android {
    compileSdkVersion 21
    buildToolsVersion "21.0.1"

    defaultConfig {
        applicationId "com.company.name"
        minSdkVersion 15
        targetSdkVersion 21
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        ...
    }
}

dependencies {
    compile 'org.simpleframework:simple-xml:2.7.1'
}

The probles is that I get an error and the message of this error that domain layer depends on libraries but is not a library itself . What's wrong there?

Answer 1

My advice would be to remove the dependency of Domain on Data. Instead, inject the data provider into domain. There is a nice article that gives a clue on how different application parts should be related to make unit testing painless.

The alternative would be to follow @frederick nyawaya's answer and use this tutorial to set up unit testing with Robolectric.

Answer 2

在你的build.gradle 域 ，添加： apply plugin: 'com.android.library'