当代码移到类中时，Arduino NeoPixel代码的行为异常

#include <Adafruit_NeoPixel.h>

#define PIN 6
#define NUMPIXELS 16

class NeoPixelController {
public:
    NeoPixelController() : pixels(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800) {
        pixels.begin();
        pixels.show(); // Initialize all pixels to 'off'
    }

    void setColor(uint16_t index, uint8_t r, uint8_t g, uint8_t b) {
        if (index < NUMPIXELS) {
            pixels.setPixelColor(index, pixels.Color(r, g, b));
            pixels.show();
        }
    }

    void clear() {
        for (uint16_t i = 0; i < NUMPIXELS; i++) {
            pixels.setPixelColor(i, pixels.Color(0, 0, 0));
        }
        pixels.show();
    }

private:
    Adafruit_NeoPixel pixels;
};

NeoPixelController npController;

void setup() {
    // No additional setup needed here
}

void loop() {
    npController.setColor(0, 255, 0, 0); // Set the first pixel to red
    delay(1000);
    npController.setColor(0, 0, 0, 0); // Turn off the first pixel
    delay(1000);
}