Android Studio - Importing Simple-Xml library

问题:

I am going crazy with my Android Studio IDE.

I am willing to add the Maven library simple-xml from Central (v2.7.1)

1. The project compiles well

2. Gradle has the lib dependency in its build.gradle:

   dependencies {
     compile 'com.android.support:appcompat-v7:18.0.0'
     compile 'org.simpleframework:simple-xml:2.7.1'
   }
   

3. Export is checked in Android Studio's Module Settings for the simple-xml lib:

Screenshot here: https://s6.postimg.cc/xxgj56zkx/Module_Settings.png

And I got the Class not found when I run my app ...

java.lang.NoClassDefFoundError: org.simpleframework.xml.core.Persister

I am lost, It sounds like Gradle doesn't pack the lib and dependencies in the apk for some reasons ...

Edit1: my Android Studio version is 0.2.13 (latest), Gradle 0.5.+

Edit2: full build.gradle I use

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:0.5.+'
    }
}
apply plugin: 'android'

repositories {
    mavenCentral()
}

android {
    compileSdkVersion 17
    buildToolsVersion "17.0.0"

    defaultConfig {
        minSdkVersion 14
        targetSdkVersion 18
    }
}

dependencies {
    compile 'com.android.support:appcompat-v7:18.0.0'
    compile 'org.simpleframework:simple-xml:2.7.1'
}

回答1:

You should add simple-xml library this way:

compile('org.simpleframework:simple-xml:2.7.1') {
    exclude group: 'stax', module: 'stax-api'
    exclude group: 'xpp3', module: 'xpp3'
}

Libraries stax-api and xpp3 are conflicting with Android classes. The classes from these jars seem to be included in Android.

Original dex message was:

trouble processing "javax/xml/stream/events/StartElement.class":

Ill-advised or mistaken usage of a core class (java.* or javax.*) when not building a core library.

This is often due to inadvertently including a core library file in your application's project, when using an IDE (such as Eclipse). If you are sure you're not intentionally defining a core class, then this is the most likely explanation of what's going on.

However, you might actually be trying to define a class in a core namespace, the source of which you may have taken, for example, from a non-Android virtual machine project. This will most assuredly not work. At a minimum, it jeopardizes the compatibility of your app with future versions of the platform. It is also often of questionable legality.

If you really intend to build a core library -- which is only appropriate as part of creating a full virtual machine distribution, as opposed to compiling an application -- then use the "--core-library" option to suppress this error message.

If you go ahead and use "--core-library" but are in fact building an application, then be forewarned that your application will still fail to build or run, at some point. Please be prepared for angry customers who find, for example, that your application ceases to function once they upgrade their operating system. You will be to blame for this problem.

If you are legitimately using some code that happens to be in a core package, then the easiest safe alternative you have is to repackage that code. That is, move the classes in question into your own package namespace. This means that they will never be in conflict with core system classes. JarJar is a tool that may help you in this endeavor. If you find that you cannot do this, then that is an indication that the path you are on will ultimately lead to pain, suffering, grief, and lamentation.

回答2:

I got the same error using maven with Android. I corrected dependency and everything worked well. It's my dependency for simple-xml library:

<dependency>
<groupId>org.simpleframework</groupId>
<artifactId>simple-xml</artifactId>
<version>2.7.1</version>
<scope>compile</scope>
<exclusions>
    <exclusion>
        <artifactId>xpp3</artifactId>
        <groupId>xpp3</groupId>
    </exclusion>
    <exclusion>
        <artifactId>stax-api</artifactId>
        <groupId>stax</groupId>
    </exclusion>
    <exclusion>
        <artifactId>stax</artifactId>
        <groupId>stax</groupId>
    </exclusion>
    <exclusion>
        <artifactId>spring-web</artifactId>
        <groupId>org.springframework</groupId>
    </exclusion>
    <exclusion>
        <artifactId>commons-logging</artifactId>
        <groupId>commons-logging</groupId>
    </exclusion>
</exclusions>
</dependency>

回答3:

I found the problem.

It was the graddle plugin 0.5.+ as I expected.

The Android Studio 0.3.0 with gradle plugin 0.6.+ (Gradle 1.8) now fixes the problem.

However, I made the application to work with the Android Studio 0.2.13 and gradle plugin 0.5 this way:

As the gradle plugin refuses to deploy the library from maven central, I downloaded the library and dependencies to the lib directory of my project. I setup the project to use the library as a local one in the lib directory of the project.

Directions for the workaround:

1. remove all references in my project to simple-xml (maven central) in Module Settings

2. Copy simple-xml-2.7.1.jar, stax-1.2.0.jar, stax-api-1.0.1.jar and xpp3-1.1.3.3.jar to lib directory in my project

3. Select the lib simple-xml-2.7.1.jar in my project and Import the lib using Add as Library contextual menu

4. Change the build.gradle like this:

   dependencies {

   compile 'com.android.support:appcompat-v7:18.0.0'
   
   compile files('simple-xml-2.7.1.jar')
   

   }

Note: do not include the dependencies, otherwise they will create conflicts with the Android system as mentionned by Grzegorz