when i compile this code it always 'sendCommand' was not declare in this scope..plzz help
In loop you have three opening braces and one closing brace. This won't end well:

void loop() { // run over and over
  if (esp8266.available()) {
    if (esp8266.find("+IPD,0,")) {
      delay(10);
      esp8266.find(":");
      delay(10);
      char letter = esp8266.read();
      Serial.print(letter); //for monitoring purposes
      //Gets the value/char from android app
    }


Two more closing braces would fix it.