#include <Keypad.h>
#include <LiquidCrystal_I2C.h>

char keys[4][4] = {
  { '1', '2', '3', 'A' },
  { '4', '5', '6', 'B' },
  { '7', '8', '9', 'C' },
  { '*', '0', '#', 'D' }
};

uint8_t colPins[4] = {23, 25, 27, 29};
uint8_t rowPins[4] = {33, 35, 37, 39};
String type = "Typed: ";
String view = "";
int asterisk_press = 0;

Keypad keypad = Keypad(makeKeymap(keys), colPins, rowPins, 4, 4);
LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
  lcd.begin(20, 4);
  lcd.setCursor(0, 0);
  lcd.print(type);
}

void loop() {
  char key = keypad.getKey();

  if (key == '#') {
    view = "";

    lcd.clear();
  } else if (key == '*') {
    asterisk_press++;

    if (asterisk_press % 2) {
      type = "Pressed: ";
    } else {
      type = "Typed: ";
    }

    lcd.clear();
  } else if (key != NO_KEY) {
    view += key;
    lcd.clear();
  }

  lcd.setCursor(0, 0);
  lcd.print(type + view);
}