Unable to get project resource file

I always get "File Not Found!". In the Xcode project tree , the FolderA color is blue it is added to where the .swift or other source files are. The FolderA name shows up in "build phases" -> Copy bundle Resources. swift version 4.x and xcode 9.x,

var fileName1 : String = ""
let FileText = "FileA"
if let textFilePath = Bundle.main.path(forResource:FileText, ofType:"txt", inDirectory:"FolderA") {
    fileName1 = textFilePath
    print("File Not Found!")

//use fileName1 in here