Android库参考无法找到project.properties

Question

在root_folder/platform/android/project.properties内。我像这样设置库引用：

android.library.reference.1=CordovaLib
android.library.reference.2=${sdk.dir}/extras/google/play_licensing/library
android.library.reference.3=${sdk.dir}/extras/google/play_apk_expansion/downloader_library
android.library.reference.4=${sdk.dir}/extras/google/play_apk_expansion/zip_file

SDK目录是正确的。但是当我尝试构建它时。它显示一个错误： .../sdk/extras/google/play_licensing/library resolve to a path with no project.properties file for project my_root_project_folder/platform/android

为什么会这样？