QListWidget默认选择项目索引

Question

我有一个QListWidget有一些项目，我有我的表单上的“删除”按钮，实际上从列表（数组对象）和QlistWidget中删除项目。

将添加项添加到数组obj中，并将其显示到QlistWidget，问题是当我按下删除而没有从列表中选择任何项目时，默认情况下它将lats索引中的项目移除并将其删除当我按下删除按钮时QlistWidget没有刷新。

我困惑该如何解释，需要尝试的代码第一

这是我的代码：

import sys 
from PyQt4.QtCore import * 
from PyQt4.QtGui import * 
from netmiko import ConnectHandler 
from paramiko import SSHException 
import jtextfsm as textfsm 
import ipaddress 
import time 

class Widget(QWidget): 
    def __init__(self, parent=None): 
     QWidget.__init__(self, parent=parent) 
     self.device_list = [] #object array 
     self.setWindowTitle("Network Automation") 
     ############################# Input IP 

     # Device Type 
     lb_device_list = QLabel(self) 
     lb_device_list.setText('Device Type') 
     self.cb_device_list = QComboBox(self) 
     self.cb_device_list.addItem('cisco_ios') 
     self.cb_device_list.addItem('cisco_s300') 

     # Ip Device 
     lb_ip = QLabel(self) 
     lb_ip.setText('IP Address') 
     self.le_ip = QLineEdit(self) 
     self.le_ip.setText('') 
     self.le_ip.setPlaceholderText('Input Device IP') 
     self.le_ip.setFixedWidth(150) 

     # username 
     lb_username = QLabel(self) 
     self.le_username = QLineEdit(self) 
     lb_username.setText('Username') 
     self.le_username.setText('') 
     self.le_username.setPlaceholderText('Input Username') 
     self.le_username.setFixedWidth(150) 

     # password 
     lb_password = QLabel(self) 
     self.le_password = QLineEdit(self) 
     lb_password.setText('Password') 
     self.le_password.setText('') 
     self.le_password.setPlaceholderText('Input Password') 
     self.le_password.setFixedWidth(150) 

     # Privilage Password 
     lb_enable = QLabel(self) 
     lb_enable.setText('Privilege Mode Password') 
     self.le_enable = QLineEdit(self) 
     self.le_enable.setText('') 
     self.le_enable.setPlaceholderText('Input Enable Password') 
     self.le_enable.setFixedWidth(150) 

     #button generate and add 
     btgenerate = QPushButton(self) 
     btgenerate.setText('Generate') 
     btgenerate.setFixedWidth(70) 
     btadd = QPushButton(self) 
     btadd.setText('Add') 

     #button delete 
     btdel = QPushButton(self) 
     btdel.setFixedWidth(70) 
     btdel.setText('Remove') 

     # line 
     line = QFrame(self) 
     line.setFrameShape(QFrame.VLine) 
     line.setFrameShadow(QFrame.Sunken) 
     line.setLineWidth(3) 

     ########################### Layout Ip Device List 

     lb3 = QLabel(self) 
     lb3.setText('IP Device List') 
     self.ip_device_list = QListWidget(self) 
     self.ip_device_list.setFixedWidth(150) 
     #self.combobox_ip_list = QComboBox(self) 
     #self.combobox_ip_list.setFixedWidth(170) 

     ############################## SubLayout and Layout 
     hblayout = QHBoxLayout() 
     hblayout.addWidget(btgenerate) 
     hblayout.addWidget(btadd) 

     sublayout = QVBoxLayout() 
     sublayout.addWidget(lb_device_list) 
     sublayout.addWidget(self.cb_device_list) 
     sublayout.addWidget(lb_ip) 
     sublayout.addWidget(self.le_ip) 
     sublayout.addWidget(lb_username) 
     sublayout.addWidget(self.le_username) 
     sublayout.addWidget(lb_password) 
     sublayout.addWidget(self.le_password) 
     sublayout.addWidget(lb_enable) 
     sublayout.addWidget(self.le_enable) 
     sublayout.addLayout(hblayout) 

     sublayout2 = QVBoxLayout() 
     sublayout2.addWidget(lb3) 
     sublayout2.addWidget(self.ip_device_list) 
     #sublayout2.addWidget(self.combobox_ip_list) 
     sublayout2.addWidget(btdel) 
     sublayout2.addStretch(1) 

     layout = QGridLayout(self) 
     layout.addLayout(sublayout,0,0) 
     layout.addWidget(line,0,1) 
     layout.addLayout(sublayout2,0,2) 

     btadd.clicked.connect(self.addDevice) 

     btdel.clicked.connect(self.remove) 



    ####################----------- AddDevice 
    def addDevice(self): 
     try: 
      ip = self.le_ip.text() 
      ipaddress.ip_address(ip) 
      device_type = str(self.cb_device_list.currentText()) 
      username = self.le_username.text() 
      password = self.le_password.text() 
      secret = self.le_enable.text() 
      command = 'show tech' 
      self.device_list.append(MyClass(device_type, ip, username, password, secret, command)) 

      # self.combobox_ip_list.addItem(ip)# Add Ip to ComboBox 
      self.ip_device_list.addItem(ip) 

      self.le_ip.clear() 
      self.le_username.clear() 
      self.le_password.clear() 
      self.le_enable.clear() 
      #self.ip_device_list.clear() 
      for list in self.device_list: 
       print(list.ip,list.device_type) 
     except ValueError: 
      print("insert you're ip correctly") 

    def remove(self): 
     index = self.ip_device_list.currentRow() 
     self.ip_device_list.takeItem(index) 
     del self.device_list[index] #dremove data from list/array 



class MyClass(object): 
    def __init__(self, device_type=None, ip=None, username=None, password=None, secret=None, command=None): 
     self.device_type = device_type 
     self.ip = ip 
     self.username = username 
     self.password = password 
     self.secret = secret 
     self.command = command 


################################## 
app = QApplication(sys.argv) 
QApplication.processEvents() 
app.setStyle('cleanlooks') 
window = Widget() 
window.show() 
sys.exit(app.exec_()) 

Answer 1

的原因是currentRow方法将返回-1如果不进行选择。在Python索引中，-1具有非常具体的含义。这意味着最后一个元素（-2将表示最后一个元素）。因此，要解决您的问题，只需将以下代码添加到您的代码中：

def remove(self): 
    index = self.ip_device_list.currentRow() 
    if index != -1: 
     self.ip_device_list.takeItem(index) 
     del self.device_list[index]