minSdkVersion < 21

android {
    defaultConfig {
        minSdkVersion 20
        multiDexEnabled true
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
}

dependencies {
	implementation 'androidx.multidex:multiDex:2.0.0'
}

让 Application 继承 MultiDexApplication

class App: MultiDexApplication() {
    override fun onCreate() {
        super.onCreate()
        // 如果有上层继承关系则使用代码方式
        MultiDex.install(this)
    }
}

minSdkVersion >= 21

android {
    defaultConfig {
        minSdkVersion 21
        multiDexEnabled true
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
}