修改应用程序或模块的build.gradle

android {
    defaultConfig {
        ...
        minSdkVersion 21 <----- *here
        targetSdkVersion 26
        multiDexEnabled true <------ *here
    }
    ...
}

根据官方文件

Multidex support for Android 5.0 and higher Android 5.0 (API level 21) and higher uses a runtime called ART which natively supports loading multiple DEX files from APK files. ART performs pre-compilation at app install time which scans for classesN.dex files and compiles them into a single .oat file for execution by the Android device. Therefore, if your minSdkVersion is 21 or higher, you do not need the multidex support library. For more information on the Android 5.0 runtime, read ART and Dalvik.

https://developer.android.com/studio/build/multidex

我所要做的就是在文件>项目结构>应用>口味中将最低SDK版本设置为21

我用这种方法解决了我同样的问题，你需要遵循2个简单的步骤。我是AndroidX用户，所以对我来说，首先我在构建中实现了这个依赖。Gradle文件在我的项目中的依赖项部分。

实现“androidx.multidex: multidex: 2.0.1”

dependencies {
//for multidex
implementation 'androidx.multidex:multidex:2.0.1'

}

在构建中添加此依赖项后。Gradle文件，然后再次同步您的项目

现在添加到“defaultConfig”部分:

multiDexEnabled真实

defaultConfig {
    applicationId "com.papel.helper"
    minSdkVersion 16
    targetSdkVersion 28
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

    multiDexEnabled true
  
}

现在重新构建你的项目并运行:)

修改应用程序或模块的build.gradle

android {
    defaultConfig {
        ...
        minSdkVersion 21 <----- *here
        targetSdkVersion 26
        multiDexEnabled true <------ *here
    }
    ...
}

根据官方文件

Multidex support for Android 5.0 and higher Android 5.0 (API level 21) and higher uses a runtime called ART which natively supports loading multiple DEX files from APK files. ART performs pre-compilation at app install time which scans for classesN.dex files and compiles them into a single .oat file for execution by the Android device. Therefore, if your minSdkVersion is 21 or higher, you do not need the multidex support library. For more information on the Android 5.0 runtime, read ART and Dalvik.

https://developer.android.com/studio/build/multidex

我不知道为什么，也许是因为我在Kotlin开发，但要修复这个错误 我最后必须创建一个扩展MultiDexApplication的类，就像这样:

class MyApplication : MultiDexApplication() {
}

然后在manifest。xml中进行设置

<application
        ...
        android:name=".MyApplication">

为了不让任何人感到困惑，我也这样做:

multiDexEnabled true
implementation 'com.android.support:multidex:1.0.3'

对于androidx，这也适用于我:

implementation 'androidx.multidex:multidex:2.0.0'

...

<应用android: name = " android.support.multidex.MultiDexApplication " >

对我没用吗

我在颤振项目中使用了以下解决方案:

志愿者项目/ app /构建开放。Gradle并添加以下行:

android {
    ...

    defaultConfig {
        ...
        
        minSdkVersion 21
        multiDexEnabled true
    }
}

then

dependencies {
    ...

    implementation 'com.android.support:multidex:1.0.3'
}

如果你已经迁移到AndroidX，你会想要这样:

dependencies {
    ...

    implementation 'androidx.multidex:multidex:2.0.1'
}

这个解决方案对我很有效。谢谢你的提问。