Arduino sketch for I2C mini OLED display

Demo 1: Hello

#include <FS.h>                   //this needs to be first, or it all crashes and burns...

#include <ESP8266WiFi.h>          //https://github.com/esp8266/Arduino

// For OLED display
#include <U8g2lib.h>

U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE);

const int pinButton = 0;

void drawDisplay(const char *line1, const char *line2 = "", const char *line3 = "")
{
  // Write on OLED display
  // Clear the internal memory
  u8g2.clearBuffer();
  // Set appropriate font
  u8g2.setFont(u8g2_font_ncenR14_tr);
  u8g2.drawStr(0,14, line1);
  u8g2.drawStr(0,39, line2);
  u8g2.drawStr(0,64, line3);
  // Transfer internal memory to the display
  u8g2.sendBuffer();
}

void setup()
{
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println();
  u8g2.begin();

  delay(10);

  //Button
  pinMode(pinButton, INPUT);

  Serial.println("Testing the OLED I2C display...");
  drawDisplay("TEST", "Hello", "World");
}

void loop()
{
  if (false == digitalRead(pinButton))
  {
    Serial.println("Rebooting...");
    // Restart the board
    ESP.restart(); 
  }
}

Demo 2: YouTube

#include <FS.h>                   //this needs to be first, or it all crashes and burns...

#include <ESP8266WiFi.h>          //https://github.com/esp8266/Arduino

// For OLED display
#include <U8g2lib.h>

U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE);

const int pinButton = 0;

void drawDisplay(const char *line1, const char *line2 = "", const char *line3 = "")
{
  // Write on OLED display
  // Clear the internal memory
  u8g2.clearBuffer();
  // Set appropriate font
  u8g2.setFont(u8g2_font_fub20_tr);
  u8g2.drawStr(0,20, line1);
  u8g2.setFont(u8g2_font_fub11_tr);
  u8g2.drawStr(0,42, line2);
  u8g2.drawStr(0,64, line3);
  // Transfer internal memory to the display
  u8g2.sendBuffer();
}

void setup()
{
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println();
  u8g2.begin();

  delay(10);

  //Button
  pinMode(pinButton, INPUT);

  Serial.println("Testing the OLED I2C display...");
  drawDisplay("YouTube", "Do you like", "this video?");
}

void loop()
{

}

Demo 3: Counter

#include <FS.h>                   //this needs to be first, or it all crashes and burns...

#include <ESP8266WiFi.h>          //https://github.com/esp8266/Arduino

// For OLED display
#include <U8g2lib.h>

U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE);

const int pinButton = 0;

void drawDisplay(const char *line1, const char *line2 = "", const char *line3 = "")
{
  // Write on OLED display
  // Clear the internal memory
  u8g2.clearBuffer();
  // Set appropriate font
  u8g2.setFont(u8g2_font_fub20_tr);
  u8g2.drawStr(0,20, line1);
  u8g2.setFont(u8g2_font_fub11_tr);
  u8g2.drawStr(0,42, line2);
  u8g2.drawStr(0,64, line3);
  // Transfer internal memory to the display
  u8g2.sendBuffer();
}

void setup()
{
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println();
  u8g2.begin();

  delay(10);

  //Button
  pinMode(pinButton, INPUT);

  Serial.println("Testing the OLED I2C display...");
  drawDisplay("YouTube", "Do you like", "this video?");
}

int counter = 0;

void loop()
{
  delay(3000);
  if (false == digitalRead(pinButton))
  {
    Serial.println("Resetting the counter...");
    drawDisplay("BUTTON", "Resetting...", "Counter: 0");
    counter = 0; 
  }
  else if (10 == counter)
  {
    Serial.println("You have reached the limit.");
    drawDisplay("LIMIT", "Resetting...", "Counter: 0");
    counter = 0;
  }
  else
  {
    counter++;
    String text = "Counter: " + String(counter);
    drawDisplay("DEMO", text.c_str(), "");
  }
}