Bulid error - 'File' was not declared in this scope

Why does it say that the ‘File’ class is not declared?
I encluded <FS.h> and it didn’t work.
so I added build_flags = -I “FS.h path” but it also didn’t work.

  • build error
src/main.cpp: In function 'void touch_calibrate()':
src/main.cpp:517:7: error: 'File' was not declared in this scope
  • main.cpp
#include "FS.h"
#include <LittleFS.h>
...

     File f = LittleFS.open(CALIBRATION_FILE, "r");
      if (f) {
        if (f.readBytes((char *)calData, 14) == 14)
          calDataOK = 1;
        f.close();
      }
  • platformio.ini
[env]
platform = espressif32
framework = arduino, espidf
monitor_speed = 115200

[env:esp-wrover-kit]
board = esp-wrover-kit
lib_deps = bodmer/TFT_eSPI@^2.4.79
build_type = debug
build_flags = 
        -I "C:\Users\JJS\.platformio\packages\framework-arduinoespressif32\cores\esp32"
        -I "C:\Users\JJS\.platformio\packages\framework-arduinoespressif32\variants\esp32"
        -I "C:\Users\JJS\.platformio\packages\framework-arduinoespressif32\libraries\FS\src"
platform_packages =
        platformio/tool-openocd-esp32@^2.1100.20220706
board_build.filesystem = littlefs   

I converted LITTLEFS_test.ino to LITTLEFS_test.cpp for littleFS function test.
I created a function littleFS_test() in the main and built it, but a link error occurred.
What could be the problem?

Linking .pio\build\esp-wrover-kit\firmware.elf
c:/users/jjs/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp-wrover-kit\src\main.o:(.literal._ZL13littleFS_testv+0x8): undefined reference to `LittleFS'
c:/users/jjs/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp-wrover-kit\src\main.o:(.literal._ZL13littleFS_testv+0x44): undefined reference to `fs::LittleFSFS::begin(bool, char const*, unsigned char, char const*)'
c:/users/jjs/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp-wrover-kit\src\main.o: in function `littleFS_test()':    
C:\Users\JJS\Documents\PlatformIO\Projects\221107-141244-espidf-arduino-wifiscan/src/main.cpp:579: undefined reference to `fs::LittleFSFS::begin(bool, char const*, unsigned char, char const*)'
  • littleFS_test() in main.cpp
void littleFS_test(void)
{ 
    if(!LittleFS.begin(FORMAT_LITTLEFS_IF_FAILED)){
        Serial.println("LittleFS Mount Failed");
        return;
    }
...
    Serial.println( "Test complete" ); 
}

This is almost always wrong. Let me double check how this can work.