Root directory/Archive file not found while importing

I am trying to import a archive file 开发者_StackOverflow中文版containing Android application project in Eclipse. But I receive a message No projects are found to import. Same goes when I am importing a root directory. Why I am getting this message?

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The project in question may not have been set up to work with Eclipse. For example, it might not have .classpath and .project files.

If so, you can still "import" it into an Android project -- start a new Android project and choose "Create project from existing source".