Wireless stick OLED screen does not display text

Hi, I have a problem, for now I just want to show a simple text on the OLED screen of my Wireless Stick board but nothing appears. The code on LoRa I think it does not affect because it works correctly.

Code Wireless Stick Board

// Heltec Wireless Stick Board
// Libraries for LoRa
#include <SPI.h>
#include <LoRa.h>

// Libraries for OLED
#include <Wire.h>
#include <SSD1306Wire.h>

// OLED related variables
#define OLED_ADDR   0x3c
#define OLED_SDA    4
#define OLED_SCL    15

// Define the pins used by the LoRa transceiver module
#define SCK   5   // GPIO5  -- SX1278 SCK
#define MISO  19  // GPIO19 -- SX1278 MISO
#define MOSI  27  // GPIO27 -- SX1278 MOSI
#define SS    18  // GPIO18 -- SX1278 CS
#define RST   14  // GPIO14 -- SX1278 RESET
#define DIO0  26  // GPIO26 -- SX1278 IRQ(Interrupt Request)

#define BAND    915E6 // 433E6 for Asia, 866E6 for Europe or 915E6 for North America

String LoRaData;

SSD1306Wire display(OLED_ADDR, OLED_SDA, OLED_SCL, GEOMETRY_64_32);

void displayText() {
  display.init();                     // Clear screen
  display.setFont(ArialMT_Plain_16);  // Format text
  display.drawString(0, 0, "test");   // Add to buffer
  display.display();                  // Displays content in buffer
}

void setup() {
  // Initialize Serial Monitor
  Serial.begin(115200);
  Serial.println("LoRa receiver");
  // SPI LoRa pins
  SPI.begin(SCK, MISO, MOSI, SS);
  // Setup LoRa transceiver module
  LoRa.setPins(SS, RST, DIO0);
  if (!LoRa.begin(BAND)) {
    Serial.println("LoRa has failed");
    while (1);
  }
  Serial.println("LoRa has started");
  delay(2000);
}

void loop() {
  int packetSize = LoRa.parsePacket();
  if (packetSize) {
    Serial.print("Receiver packet '");
    while (LoRa.available()) {
      LoRaData = LoRa.readString();
      Serial.print(LoRaData);
    }
    int rssi = LoRa.packetRssi();
    Serial.print("' with RSSI ");
    Serial.print(rssi);
    Serial.println("");
  }
  displayText();
}

You can refer to these codes(https://github.com/HelTecAutomation/Heltec_ESP32/tree/master/examples/OLED) to modify your OLED part.