When the XML file in the layout file in Android is properly matched, the corresponding code cannot be generated automatically in the R class

Reasons for not being updated:
   1. Incorrect or malformed code in the XML file
   The 2.eclipse compiler is the old version
   3. The file name of the layout files has uppercase letters
   4. xml file containing the same file name and format
Workaround:
1. Find the error code format correction in the error XML file and perform the Project-clean operation
2.eclipse Select Project--build automaticaly, remove the above tick

When the XML file in the layout file in Android is properly matched, the corresponding code cannot be generated automatically in the R class