Android 4 上 Android Studio 的 NoClassDefFoundError

问题描述

我正在将现有应用从 Eclipse 转换为 Android Studio.但是，当我在运行 4.x 的设备上运行它时(我已经在模拟器上测试了几个版本)，它立即崩溃并出现 NoClassDefFoundError.

I'm in the process of converting an existing app from Eclipse to Android Studio. However, when I run it on a device running 4.x (I've tested several versions on emulators), it immediately crashes with a NoClassDefFoundError.

我已经尝试注释掉对它找不到的类的引用，但总会有另一个.据我所知，有问题的班级总是

I've tried commenting out references to the classes it can't find, but there's always another. As far as can tell, the offending class is always

1. 在我自己的代码中
2. 一个内部类(更新:经过更多调查，这并不总是正确的)

1. Within my own code
2. An inner class (Update: With more investigation, this one isn't always true)

在 5.0.1 模拟器上一切正常(我没有要测试的设备).我的 build.gradle 文件相当长，但看起来像这样:

Everything works fine on a 5.0.1 emulator (I don't have a device to test on). My build.gradle file is fairly long, but looks like this:

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

def AAVersion = "2.7.1"

android {
    compileSdkVersion 19
    buildToolsVersion "21.1.1"

    defaultConfig {
        applicationId "com.myapp.android"
        minSdkVersion 8
        targetSdkVersion 19
        multiDexEnabled = true
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
        }
    }

    packagingOptions {
        *snip*
    }
}

buildscript {
    repositories {
        mavenCentral()

    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.0.0'
        classpath 'com.neenbedankt.gradle.plugins:android-apt:1.4'
    }
}

repositories {
    maven {
        url "https://repo.commonsware.com.s3.amazonaws.com"
    }
}

apt {
    arguments {
        androidManifestFile variant.outputs[0].processResources.manifestFile
        resourcePackageName 'com.pact.android'
    }
}

dependencies {
    *snip compile project(':...') declarations

    apt "com.googlecode.androidannotations:androidannotations:$AAVersion"
    compile "com.googlecode.androidannotations:androidannotations-api:$AAVersion"

    compile 'com.actionbarsherlock:actionbarsherlock:4.4.0@aar'
    compile 'com.android.support:support-v4:21.0.3'
    compile 'com.google.android.gms:play-services:3.1.36'

    *snip many more compile declarations*

    compile fileTree(dir: 'libs', include: ['*.jar'])
}

导致麻烦的类的一些例子:

Some examples of classes that cause trouble:

• 在 facebook 库中实现接口的匿名类(作为库项目)
• Parcelable.CREATOR 在我的模型中实现
• 扩展 android.os.Library 的内部类
• 我自己代码中的内部类
• 在 maven 库中实现接口的类

出了什么问题，我该如何解决?

What's going wrong, and how do I fix it?

推荐答案

我没有完全实现 MultiDex 支持，所以我的一些类不在正确的 dex 文件中.要修复它，您需要做的不仅仅是在 defaultConfig 块中设置 multiDexEnabled = true.您还必须:

I was incompletely implementing MultiDex support, so some of my classes weren't in the proper dex file. To fix it, you have to do more than just set multiDexEnabled = true in your defaultConfig block. You also have to:

1. 在您的依赖项中包含 compile 'com.android.support:multidex:1.0.1'
2. 让您的应用程序类扩展 MultiDexApplication 而不仅仅是 Application.或者，您可以在应用程序的 attachBaseContext() 中调用 MultiDex.install().

1. Include compile 'com.android.support:multidex:1.0.1' in your dependencies
2. Have your Application class extend MultiDexApplication instead of just Application. Alternatively, you can call MultiDex.install() in attachBaseContext() of your application.

请参阅 https://developer.android.com/tools/building/multidex.html 了解更多细节.

See https://developer.android.com/tools/building/multidex.html for more details.

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