python - 如何使用 python 中的 evdev 从 hid 设备(条形码扫描仪)获取有效的可理解字符串

Question

我一直在尝试在 python 中使用条形码扫描仪和 evdev 来获取字符串输出。这是我的脚本...

from evdev import *
dev = InputDevice('/dev/input/event2')

print(dev)

for event in dev.read_loop():
    if event.type == ecodes.EV_KEY:
        print(categorize(event))

当我扫描此后，我得到以下输出:

key event at 1526024323.229556, 5 (KEY_4), down
key event at 1526024323.237564, 5 (KEY_4), up
key event at 1526024323.245549, 11 (KEY_0), down
key event at 1526024323.253534, 11 (KEY_0), up
key event at 1526024323.261553, 2 (KEY_1), down
key event at 1526024323.269538, 2 (KEY_1), up
key event at 1526024323.277549, 10 (KEY_9), down
key event at 1526024323.285565, 10 (KEY_9), up
key event at 1526024323.293555, 2 (KEY_1), down
key event at 1526024323.301535, 2 (KEY_1), up
key event at 1526024323.309553, 7 (KEY_6), down
key event at 1526024323.317533, 7 (KEY_6), up
key event at 1526024323.325553, 10 (KEY_9), down
key event at 1526024323.333537, 10 (KEY_9), up
key event at 1526024323.341554, 3 (KEY_2), down
key event at 1526024323.349537, 3 (KEY_2), up
key event at 1526024323.357552, 2 (KEY_1), down
key event at 1526024323.365537, 2 (KEY_1), up
key event at 1526024323.373554, 2 (KEY_1), down
key event at 1526024323.381535, 2 (KEY_1), up
key event at 1526024323.389555, 3 (KEY_2), down
key event at 1526024323.397535, 3 (KEY_2), up
key event at 1526024323.405552, 4 (KEY_3), down
key event at 1526024323.413537, 4 (KEY_3), up
key event at 1526024323.421554, 10 (KEY_9), down
key event at 1526024323.429537, 10 (KEY_9), up
key event at 1526024323.437579, 28 (KEY_ENTER), down
key event at 1526024323.445533, 28 (KEY_ENTER), up

我什么都不明白，因为我是Python新手，但我认为在这种情况下这不会有太大区别。我已经检查了其他相关问题，但无法使它们的答案起作用。请大家帮帮我。

如何过滤掉优点并保留缺点。

Answer 1

条形码扫描仪通常(总是？)充当键盘。使用条形码扫描仪扫描条形码在计算机上的显示与插入键盘、输入数字并按 Enter 键完全相同。

如果您打开命令提示符或文本编辑器并扫描某些内容，您是否会看到该数字就像您键入的一样？

通常您不需要使用低级接口(interface)与之交互 - 只需使用内置的 input()