Android Gradle Plugin 3.0.0: Multiple dex files define Lorg/xmlpull/mxp1/MXParser with XStream

Question

Included projects that bring their own xmlpullparser always needed some extra care in Android Studio since Android brings its own xmlpullparser.

E.g. t

Answer 1

Finally I found the fix. However, I am still puzzled why it depended on the Gradle Plugin Version.

I am using logback-android that somehow depends on xpp3 as you can see on the dependency graph:

    +--- com.github.tony19:logback-android-classic:1.1.1-6
|    |    +--- com.github.tony19:logback-android-core:1.1.1-6
|    |    \--- com.github.tony19:apktool-lib:1.4.4-3
|    |         \--- com.google.android:android:2.1_r1
|    |              +--- commons-logging:commons-logging:1.1.1
|    |              +--- org.apache.httpcomponents:httpclient:4.0.1
|    |              |    +--- org.apache.httpcomponents:httpcore:4.0.1
|    |              |    +--- commons-logging:commons-logging:1.1.1
|    |              |    \--- commons-codec:commons-codec:1.3
|    |              +--- org.khronos:opengl-api:gl1.1-android-2.1_r1
|    |              +--- xerces:xmlParserAPIs:2.6.2
|    |              \--- xpp3:xpp3:1.1.4c

It must be said that I declared logback-android in a utils module which I then included into my app using implementation project(:'myUtilsModule')

Now I excluded the group xpp3 with its module xpp3. The group and module names xmlpull wouldn't work.:

// https://mvnrepository.com/artifact/com.github.tony19/logback-android-classic
implementation('com.github.tony19:logback-android-classic:1.1.1-6') {
    exclude group: 'xpp3', module: 'xpp3'  //in order to avoid "Multiple dex files define Lorg/xmlpull/v1/XmlPullParser;"
    //exclude group: 'xmlpull', module: 'xmlpull' //This works usually on other libs to exclude xmlpull, but not on that one
}

I learnt the hard way how to read the dependency graph and how to exclude items from the graph ;)

1. Run How do I show dependencies tree in Android Studio?
2. Each line in the dependency graph has the format ::
3. which maps to the exclude arguments exclude group: '', module: '' or just exclude module: ''

Update: With logback-android-1.1.1-7+ the exclude is no longer necessary.