我最近将我的项目迁移到了androidx，现在我可以找到FileUtils类 .
这是我的build.gradle文件 .
implementation "androidx.appcompat:appcompat:1.0.0-rc02"
implementation "androidx.percentlayout:percentlayout:1.0.0-rc02"
implementation "androidx.browser:browser:1.0.0-rc02"
implementation "androidx.cardview:cardview:1.0.0-rc02"
implementation "androidx.legacy:legacy-support-v4:1.0.0-rc02"
implementation "com.google.android.material:material:1.0.0-rc02"