pyqt5 失焦 无操作监听 

以下内容转自：

如何捕获PyQt5 QMainWindow失去焦点-python黑洞网

timer可以更新ui。 

class MainUi(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        self.init_ui()
        self.setFocus()
        QtWidgets.qApp.focusChanged.connect(self.on_focusChanged)
    @QtCore.pyqtSlot("QWidget*", "QWidget*")
    def on_focusChanged(self, old, now):
        if now == None:
            print(f"\nwindow lost focus: {self.isActiveWindow()}",time.strftime('%Y-%m-%d %H:%M:%S'))
            # self.setWindowState(QtCore.Qt.WindowMinimized)
            self.loss_start = time.time()  # 记录开始时间
            self.timer.start(1000*5)  # 设置计时间隔并启动,1秒
    def lose_focus(self):
        if not self.isActiveWindow():