jq.parent()是什么作用

在 jQuery 中，`parent()` 方法返回被选元素的直接父元素。它可以用来遍历 DOM 树，查找元素的父元素。

例如，假设我们有如下 HTML 代码：

<div class="parent">
  <p class="child">This is a child element.</p>
</div>

我们可以使用以下 jQuery 代码来选取该 `p` 元素的父元素：

var parentElement = $('.child').parent();

在这个例子中，`parentElement` 变量将包含 `div` 元素，即 `.child` 元素的直接父元素。

注意，`parent()` 方法只会返回被选元素的直接父元素，而不是祖先元素。如果您需要遍历元素的所有祖先元素，可以使用 `parents()` 方法。

相关问题

self.main_ui.pushButton_2.clicked.connect(self.thing1) 没反应是为什么 class Worker(QtCore.QThread): sinOut = pyqtSignal(str) def __init__(self, parent=None): super(Worker, self).__init__(parent) # 设置工作状态与初始num数值 self.working = True self.num = 0 #def __del__(self): # 线程状态改变与线程终止 #self.working = False #self.wait() def stop(self): #线程状态改变与线程终止 self.working = False self.wait() def run(self): self.working = True while self.working == True: #file_str = 'File index{0}'.format(self.num) self.num += 1 # 发射信号 #self.sinOut.emit(file_str) self.sinOut.emit('1') # 线程休眠2秒 self.msleep(5) class parentWindow(QMainWindow): def __init__(self): QMainWindow.__init__(self) self.main_ui = JQ.Ui_MainWindow() self.main_ui.setupUi(self) self.thread1 = Worker() self.main_ui.pushButton_2.clicked.connect(self.thing1) self.thread1.sinOut.connect(self.printt) def thing1(self): #self.main_ui.pushButton.setEnabled(False) print('9999999999') self.thread1.start() print('123') #self.sleep(2) def printt(self): print('7777') def ok(): print('ok') # def hourstest(): # thread1 = Worker() # thread1.start() # com = JQ.Ui_MainWindow().comboBox_2.currentText() # ser = serial.Serial('com3', 1200, timeout=1) # data = bytes.fromhex( # '68 01 00 20 00 00 00 00 00 34 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 33 F4 16 ') # ser.write(data) if __name__ == "__main__": app = QtWidgets.QApplication(sys.argv) widget = QtWidgets.QMainWindow() widget = parentWindow() ui = JQ.Ui_MainWindow() # 这是原py中的类,因人而异哦 ui.setupUi(widget) ui.discoverSerial() #串口发现 #ui.pushButton_2.clicked.connect(widget.thing1) widget.show() sys.exit(app.exec_())

首先，你的连接语句应该是正确的。但是，你的槽函数`thing1`中启动了一个线程并且没有等待该线程完成。因此，当你再次点击`pushButton_2`时，会创建一个新的线程，导致出现问题。

你需要在`thing1`函数中添加`self.thread1.wait()`语句来等待线程完成。这样，当你再次点击`pushButton_2`时，它会等待线程完成后再启动一个新的线程。

另外，你在`ok`函数中定义了一个serial对象，但是没有使用它。如果你想使用该对象，你需要在该函数中添加相关代码。

以下是修改后的代码：

class parentWindow(QMainWindow):
    def __init__(self):
        QMainWindow.__init__(self)
        
        self.main_ui = JQ.Ui_MainWindow()
        self.main_ui.setupUi(self)
        
        self.thread1 = Worker()
        self.thread1.sinOut.connect(self.printt)
        self.main_ui.pushButton_2.clicked.connect(self.thing1)

    def thing1(self):
        print('9999999999')
        self.thread1.start()
        self.thread1.wait()  # 等待线程完成
        print('123')

    def printt(self):
        print('7777')

def ok():
    print('ok')
    com = JQ.Ui_MainWindow().comboBox_2.currentText()
    ser = serial.Serial('com3', 1200, timeout=1)
    data = bytes.fromhex('68 01 00 20 00 00 00 00 00 34 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 33 F4 16   ')
    ser.write(data)

这段代码没进 thing1()的原因 class Worker(QtCore.QThread): sinOut = pyqtSignal(str) def __init__(self, parent=None): super(Worker, self).__init__(parent) # 设置工作状态与初始num数值 self.working = True self.num = 0 #def __del__(self): # 线程状态改变与线程终止 #self.working = False #self.wait() def stop(self): #线程状态改变与线程终止 self.working = False self.wait() def run(self): self.working = True while self.working == True: #file_str = 'File index{0}'.format(self.num) self.num += 1 # 发射信号 #self.sinOut.emit(file_str) self.sinOut.emit('1') # 线程休眠2秒 self.msleep(5) class parentWindow(QMainWindow): def __init__(self): QMainWindow.__init__(self) self.main_ui = JQ.Ui_MainWindow() self.main_ui.setupUi(self) self.thread1 = Worker() self.main_ui.pushButton_2.clicked.connect(self.thing1) self.thread1.sinOut.connect(self.printt) def thing1(self): #self.main_ui.pushButton.setEnabled(False) print('9999999999') self.thread1.start() self.thread1.wait() print('123') #self.sleep(2) def printt(self): print('7777') def ok(): print('ok') # def hourstest(): # thread1 = Worker() # thread1.start() # com = JQ.Ui_MainWindow().comboBox_2.currentText() # ser = serial.Serial('com3', 1200, timeout=1) # data = bytes.fromhex( # '68 01 00 20 00 00 00 00 00 34 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 33 F4 16 ') # ser.write(data) if __name__ == "__main__": app = QtWidgets.QApplication(sys.argv) widget = QtWidgets.QMainWindow() widget = parentWindow() ui = JQ.Ui_MainWindow() # 这是原py中的类,因人而异哦 ui.setupUi(widget) ui.discoverSerial() #串口发现 #ui.pushButton_2.clicked.connect(widget.thing1) widget.show() sys.exit(app.exec_())

在你的代码中，`thing1()` 函数中调用了 `self.thread1.wait()` 方法，这个方法会阻塞主线程，直到子线程执行完毕。因此，如果在 `thing1()` 中调用 `self.thread1.start()` 方法后立即调用 `self.thread1.wait()` 方法，那么子线程就没有机会执行 `run()` 方法，因为主线程一直在等待子线程执行完毕。

解决方法是在 `thing1()` 中删除 `self.thread1.wait()` 方法，让子线程在后台执行。同时，建议在 `Worker` 类的 `__del__()` 方法中加入线程终止的代码，以确保线程能够正确地退出。具体来说，可以将 `__del__()` 方法的注释部分取消注释，代码如下：

class Worker(QtCore.QThread):
    sinOut = pyqtSignal(str)
    
    def __init__(self, parent=None):
        super(Worker, self).__init__(parent)
        # 设置工作状态与初始num数值
        self.working = True
        self.num = 0
    
    def __del__(self):
        # 线程状态改变与线程终止
        self.working = False
        self.wait()
    
    def stop(self):
        #线程状态改变与线程终止
        self.working = False
        self.wait()
    
    def run(self):
        self.working = True
        while self.working == True:
            #file_str = 'File index{0}'.format(self.num)
            self.num += 1
            # 发射信号
            #self.sinOut.emit(file_str)
            self.sinOut.emit('1')
            # 线程休眠2秒
            self.msleep(5)

class parentWindow(QMainWindow):
    def __init__(self):
        QMainWindow.__init__(self)
        self.main_ui = JQ.Ui_MainWindow()
        self.main_ui.setupUi(self)
        self.thread1 = Worker()
        self.main_ui.pushButton_2.clicked.connect(self.thing1)
        self.thread1.sinOut.connect(self.printt)
    
    def thing1(self):
        #self.main_ui.pushButton.setEnabled(False)
        print('9999999999')
        self.thread1.start()
        #self.thread1.wait()  # 删除这行
        print('123')
        #self.sleep(2)
    
    def printt(self):
        print('7777')
    
def ok():
    print('ok')

# def hourstest():
#     thread1 = Worker()
#     thread1.start()
#     com = JQ.Ui_MainWindow().comboBox_2.currentText()
#     ser = serial.Serial('com3', 1200, timeout=1)
#     data = bytes.fromhex(
#         '68 01 00 20 00 00 00 00 00 34 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 33 F4 16   ')
#     ser.write(data)

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    #widget = QtWidgets.QMainWindow()  # 这行可删除
    widget = parentWindow()
    ui = JQ.Ui_MainWindow()  # 这是原py中的类,因人而异哦
    ui.setupUi(widget)
    ui.discoverSerial()  #串口发现
    #ui.pushButton_2.clicked.connect(widget.thing1)
    widget.show()
    sys.exit(app.exec_())