Android studio编程时出现的错误：unspecified on project app resolves to an APK archive which is not supported

用Android Studio中导入第三方库工程的时候出现的问题：

Error:Dependency MyApplication.libraries:MaterialDesign:unspecified on project app resolves to an APK archive which is not supported as a compilation dependency. File: D:\ADTBundle\StudioWorkspace\MyApplication\libraries\MaterialDesign\build\outputs\apk\MaterialDesign-release-unsigned.apk

出现该问题unspecified on project app resolves to an APK archive which is not supported as a compilation dependency的问题可能是：创建了两个Module，其中一个Module依赖另一个Module而导致了出现该问题；

在导入的那个第三方库的build.gradle，里面可以看到：

apply plugin: 'com.android.application'  

这句话是Gradle将导入的第三方库编译称为application，也就是apk，这就是问题的所在；

解决方法：将上面该句改为：

apply plugin: 'com.android.library' 

此时，Gradle将编译称为一个Library，也就是库，

运行之后，如果出现这个问题：

Error:Library projects cannot set applicationId. applicationId is set to 'package_name' in default config.

那是因为这个库不允许设置applicationId，

将第三方库的build.gradle：android — defaultConfig 中的applicationId 删除 即可；

然后问题即可解决~