¿Por qué R no existe error viene en Android?

Question

Dec 27, 2010, 05:53 AM

android user-interface compilation r.java-file

¿Por qué R no existe error viene en Android?

packages/apps/Myfolder/src/com/android/myfolder/MyFile.java:196: package R does not exist
                  addPreferencesFromResource(R.xml.myfile);
                                              ^
packages/apps/Myfolder/src/com/android/myfolder/MyFile.java:344: package R does not exist
        menu.add(0, MENU_SAVE, 0, R.string.menu_save)
                                   ^
packages/apps/Myfolder/src/com/android/myfolder/MyFile.java:346: package R does not exist
        menu.add(0, MENU_CANCEL, 0, R.string.menu_cancel)
                                     ^
packages/apps/Myfolder/src/com/android/myfolder/MyFile.java:454: package R does not exist
                     errorMsg = mRes.getString(R.string.error_empty);
                                                ^
packages/apps/Myfolder/src/com/android/myfolder/MyFile.java:458: package R does not exist
                     errorMsg = mRes.getString(R.string.error_empty);