def start(): global img, pre_pts try: root = tk.Tk() root.withdraw() f_path = filedialog.askopenfilename() if not f_path: messagebox.showinfo('提示', '请选取有效图片') else: img = cv.imread(f_path) pre_pts = -1, -1 cv.namedWindow('picture', cv.WINDOW_NORMAL) cv.resizeWindow('picture', 256, 256) cv.moveWindow('picture', 600, 300) cv.imshow('picture', img) cv.setMouseCallback('picture', draw) cv.waitKey(0) cv.destroyAllWindows() root.destroy() except Exception as e: print("出现错误:", e) 报错后如何修改可以使下面主界面可以重新点击执行start函数，且改start函数和主界面不在同一个py文件中：class Faceshow(QMainWindow, Ui_MainWindow): def init(self, parent=None): super(Faceshow, self).init(parent) self.setupUi(self) self.main_button.clicked.connect(start)

你可以在 start 函数结尾处添加一个 return 语句，并在主界面中调用该函数时判断返回值是否为 None，如果是，则不进行任何操作，否则执行其他代码。具体修改如下：

def start():
    global img, pre_pts
    try:
        root = tk.Tk()
        root.withdraw()
        f_path = filedialog.askopenfilename()
        if not f_path:
            messagebox.showinfo('提示', '请选取有效图片')
            return None
        else:
            img = cv.imread(f_path)
            pre_pts = -1, -1
            cv.namedWindow('picture', cv.WINDOW_NORMAL)
            cv.resizeWindow('picture', 256, 256)
            cv.moveWindow('picture', 600, 300)
            cv.imshow('picture', img)
            cv.setMouseCallback('picture', draw)
            cv.waitKey(0)
            cv.destroyAllWindows()
        root.destroy()
    except Exception as e:
        print("出现错误:", e)

class Faceshow(QMainWindow, Ui_MainWindow):
    def __init__(self, parent=None):
        super(Faceshow, self).__init__(parent)
        self.setupUi(self)
        self.main_button.clicked.connect(lambda: self.start())

    def start(self):
        start()
        # 如果 start 函数返回值为 None，则不进行任何操作
        if start() is None:
            pass
        else:
            # 执行其他代码
            pass