android - 使用 .aar 文件时出现 NoClassDefFoundError

Question

我有一个 .aar 文件，我将其添加到 libs 文件夹和我拥有的 gradle 中

compile(name:'file-name', ext:'aar')

它编译得很好，但是当我运行它时我得到:

System.err: java.lang.NoClassDefFoundError: com.app.foo.MUtil$3

现在这个MUtil 类 用于我在我的应用程序中使用的.aar 库 的API 方法中。我可以在 exploded-aar 文件夹中看到 MUtil 类，我什至可以通过 ctrl+click 转到该类以了解其用法。但仍然是 NoClassDefFoundError。为什么？

Gradle 文件

apply plugin: 'com.android.application'
apply plugin: 'maven'
apply plugin: 'com.neenbedankt.android-apt'

repositories {
    mavenCentral()
    maven { url 'https://clojars.org/repo/' }
    maven { url 'https://oss.sonatype.org/content/repositories/snapshots' }

    flatDir {
        dirs 'libs'
    }
}

android {
    compileSdkVersion 23
    buildToolsVersion "22.0.1"

    defaultConfig {
        applicationId "com.xxx.xxx"
        minSdkVersion 16
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    packagingOptions {
        exclude 'META-INF/services/javax.annotation.processing.Processor'
    }
    productFlavors {
    }

    lintOptions {
        abortOnError false
    }
}

buildscript {
    repositories {
        mavenCentral()
    }

    dependencies {
        classpath 'com.neenbedankt.gradle.plugins:android-apt:1.4'
        classpath 'com.android.tools.build:gradle:1.2.3'
    }
}


dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:cardview-v7:23.0.+'
    compile 'com.android.support:recyclerview-v7:23.0.+'
    compile 'com.android.support:appcompat-v7:23.1.1'
    compile('xx.xxx.xxxx:xx-xxx:0.1.2@aar') {
        transitive = true
    }
}

task wrapper(type: org.gradle.api.tasks.wrapper.Wrapper) {
    gradleVersion = '2.5'
}

Answer 1

System.err: java.lang.NoClassDefFoundError: com.app.foo.MUtil$3

NoClassDefFoundError

is thrown when the definition of class in not available during runtime .

最后

As per Javadoc NoClassDefFoundError can be thrown during linking or loading of class file. It's denoted by java.lang.NoClassDefFoundError and comes when that particular class is present during compile time but some how not available during runtime.

您可以分享您的 build.gradle 。 aar 文件的最常见错误。

Clean-Rebuild-Restart-Sync 并重试。

编辑

  buildToolsVersion "23.0.1"