Work for me 1文件>关闭投影。2打开一个现有的Android Studio项目

我在Android Studio 4.0.1上得到这个错误。这是我的解决方案:去你的构建。gradle(Module: app)文件，然后更新compileSdkVersion和buildToolsVersion。

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.2"
}

buildToolsVersion可能在应用程序的build.gradle中丢失

buildToolsVersion "26.0.3"

像这样加起来

Source Compatibility should be selected as the minimum Android Version that your app should be compatible with(usually selected as SDK 15), Target Compatibility should be selected as the newest Android Version that your app should be compatible with(SDK 23). Afterwards you want to check your AndroidMenifest and your gradle.build to see if its realy set to the properties selected if not you can just add it manually. and ofcourse you should check the SDK Location is actually pointing to your android studio SDK folder (if you are importing from Eclipse then you should point to your Eclipse SDK folder).

对于Android Studio 3.5，“File -> Sync project with gradle files”就足够了。

从android工作室点击File菜单。

文件->设置->系统设置-> Android SDK