android導入源碼缺少R.java

導入一個現存的android源碼項目的時候會缺少R.java，有的的確可以通過android tools解決，有的不行，編譯android時，遇到報錯：

	Errors occurred during the build.Errors running builder 'Android Pre Compiler' on project 'XXX'
	java.lang.NullPointerException

錯誤原因：

	工程目錄下有很多.svn目錄

解決方法：

1. Open properties of project in Eclipse then Resources -> Resource filters.
2. Click the "Add..." button -> Check "Exclude all", "Files and folders", "All children". In the text entry box input ".svn" (without quotes).
3. Restart Eclipse.