Android 使用DropBox SDK发现重复的类

使用DropBox sdk 3.1.3时出现以下错误：

Duplicate class com.dropbox.core.AccessErrorException found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.ApiErrorResponse found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.ApiErrorResponse$Serializer found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.BadRequestException found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.BadResponseCodeException found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.BadResponseException found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxApiException found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxAppInfo found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxAppInfo$1 found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxAppInfo$2 found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxAppInfo$3 found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxAuthFinish found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxAuthFinish$1 found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxAuthFinish$2 found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxAuthFinish$3 found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxAuthInfo found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxAuthInfo$1 found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxAuthInfo$2 found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxDownloader found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)
Duplicate class com.dropbox.core.DbxException found in modules dropbox-core-sdk-3.1.3.jar (com.dropbox.core:dropbox-core-sdk:3.1.3) and dropbox-core-sdk-3.1.3.jar (dropbox-core-sdk-3.1.3.jar)

这是我的build.gradle文件内容：

apply plugin: 'com.android.application'

android {
    compileSdkVersion 29
    buildToolsVersion "29.0.2"
    defaultConfig {
        applicationId "com.home.styles"
        minSdkVersion 21
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'androidx.appcompat:appcompat:1.0.2'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.0'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
    implementation 'com.dropbox.core:dropbox-core-sdk:3.1.3'
}

只有一个库文件附加在/libs下。

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我的项目中以前有过上述SDK的1.6.x版本，我将其删除并替换为更新的版本（如果这会导致此错误）。

问题是，我只导入了一个库，从日志文件看，似乎有相同库的副本，并且它们存在冲突。您看到答案了吗？我已经列出了所有可能导致重复上课的情况。