为什么 Android R SDK 在 Marshmallow 中不起作用？

我将我的 SDK 版本更新为最新的 API 级别 30 (R)，即所谓的 Android 11。现在，它在 Android R 模拟器中完美运行，但是当我尝试在棉花糖版本上运行时，它给出了以下异常。我试图删除所有 SDK 和清理/重建项目，使缓存/重启无效。

  **Exception:**
    Installation did not succeed.
    The application could not be installed: INSTALL_FAILED_OLDER_SDK
    The application's minSdkVersion is newer than the device API level.

它只适用于 Android R。我该怎么办？

android {
    compileSdkVersion 'android-R'
    defaultConfig {
        applicationId "com.lifetrenz.lifetrenz_gcc_doctorapp"
        minSdkVersion 21
        targetSdkVersion 'R'
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

我想测试从 API 21 到 API R 的应用程序

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'com.google.android.material:material:1.1.0'
    testImplementation 'junit:junit:4.13'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'

    //Lifecycle components
    def life_versions = "2.2.0-beta01"

    implementation "android.arch.lifecycle:extensions:$life_versions"
    annotationProcessor "android.arch.lifecycle:compiler:$life_versions"

    //Server API Integration
    implementation 'com.squareup.retrofit2:retrofit:2.7.1'
    implementation 'com.squareup.retrofit2:converter-gson:2.7.1'
    implementation "com.squareup.okhttp3:logging-interceptor:4.4.0"
    implementation 'com.squareup.retrofit2:adapter-rxjava2:2.7.1'

    //For QR Scanner
    implementation 'com.google.android.gms:play-services-vision:19.0.0'
}