cv2.waitKey（0）返回无

Question

I tried work with

if cv2.waitKey(0) & 0xFF == ord('q'):
        break 

But I kept on getting TypeError . However, when I use either one my camera does not respond to the code.

import cv2
import numpy as np

capture = cv2.VideoCapture(0)


while True:
    ret, frame = capture.read()
    cv2.imshow("frame", frame)

    if cv2.waitKey(0) & 0xFF == ord('q'):
        break

capture.release()
cv2.destroyAllWindows()

if cv2.waitKey(0) & 0xFF == ord('q'):

TypeError: unsupported operand type(s) for &: 'NoneType' and 'int'

Process finished with exit code 1

Answer 1

Although the docs state the waitkey function returns the code of the pressed key, you could pull out the value and perform a none check

c = cv2.waitKey(0)
if c is not None and c & 0xFF == ord('q'):