“表”对象没有属性“tableWidget”PyQt5

Question

我正在尝试更改 QTableWidget 鼠标按下事件方法，以根据用户是右键单击还是左键单击来对单元格项执行不同的操作。当我左键单击 self.tableWidget 中的单元格时出现以下错误：

AttributeError: 'Table' object has no attribute 'tableWidget' (line 114 [commented below])

下面是我的代码：

from PyQt5 import QtCore, QtGui, QtWidgets
from WordSearch import WordSearch as ws

ws = ws()


class Table(QtWidgets.QTableWidget): #overwriting QTableWidgets to allow for right click events
    def __init__(self, *args, **kwargs):
        QtWidgets.QTableWidget.__init__(self, *args, **kwargs)

    def mousePressEvent(self, event):
        if event.button() == QtCore.Qt.LeftButton:
            item = self.itemAt(event.pos())
            print (item.row(), item.column()) #FOR DEBUGGUNG
            Ui_MainWindow.leftClickLetter(self, item.row(), item.column())

        elif event.button() == QtCore.Qt.RightButton:
            print("RIGHT CLICK!") #FOR DEBUGGING
        QtWidgets.QTableWidget.mousePressEvent(self, event)

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
         .....

         self.generate.clicked.connect(self.generateTable)

         .....

    def generateTable(self):

        self.tableWidget = Table(self.centralwidget)
        self.tableWidget.setObjectName("tableWidget")

        self.tableWidget.setColumnCount(int(self.size.text()))
        self.tableWidget.setRowCount(int(self.size.text()))

        self.tableWidget.show()

    def leftClickLetter(self, row, col): 
        item = self.tableWidget.item(row, col) #Line 114
        item.setBackground(QtGui.QColor(216,191,216))
        if (row, col) not in self.coordsToCheck:
            self.coordsToCheck.append((row,col))

        self.tableWidget.clearSelection()

我删除了一些我认为不相关的代码，但如果我应该添加它，请告诉我。 generateTable() 总是在 leftClickLetter() 之前调用，所以 self.tableWidget 应该是正确的 Table 类型变量名。

Answer 1

说明：

要理解问题，应该分析下面的例子：

class A:
    def foo(self, arg1, arg2):
        print(self)


class B:
    pass


b = B()
A.foo(b, "2", 3)

输出：

<__main__.B object at 0x7fb364501070>

如您所见，对象“self”不是指“A”实例，而是指传递给方法的第一个参数，为什么会出现这个问题？好吧，因为您试图通过类使用方法，但您必须使用实例，例如：

b = B()
a = A()
a.foo(b, "2")

输出：

<__main__.A object at 0x7fd3139a4f40>

我们看到“self”指的是“A”类的对象。

_{以上是由于对OOP知之甚少而导致的错误，所以我的建议是查看您关于该主题的笔记。}

解决办法：

注意：首先不建议修改Qt Designer生成的类，所以必须恢复类，这样我的方案才能应用。

在您的情况下，没有必要覆盖任何方法，因为有几个信号会通知您是否单击了某个项目：

• itemClicked

  from PyQt5 import QtCore, QtGui, QtWidgets
  
  
  class Ui_MainWindow(object):
      def setupUi(self, MainWindow):
          # ..
  
  
  class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
      def __init__(self, parent=None):
          super().__init__(parent)
          self.setupUi(self)
          self.generate.clicked.connect(self.generate_table)
          self.coordsToCheck = []
          self.tables = []
  
      def generate_table(self):
  
          try:
              size = int(self.size.text())
          except ValueError as e:
              print("error", e)
          else:
              tableWidget = QtWidgets.QTableWidget()
              tableWidget.setColumnCount(size)
              tableWidget.setRowCount(size)
              tableWidget.show()
              tableWidget.itemClicked.connect(self.on_item_clicked)
              self.tables.append(tableWidget)
  
      @QtCore.pyqtSlot("QTableWidgetItem*")
      def on_item_clicked(self, it):
          row, col = it.row(), it.column()
          it.setBackground(QtGui.QColor(216, 191, 216))
          if (row, col) not in self.coordsToCheck:
              self.coordsToCheck.append((row, col))
          it.tableWidget().clearSelection()
  
  
  if __name__ == "__main__":
      import sys
  
      app = QtWidgets.QApplication(sys.argv)
      w = MainWindow()
      w.show()
      sys.exit(app.exec_())
  

• clicked

  from PyQt5 import QtCore, QtGui, QtWidgets
  
  
  class Ui_MainWindow(object):
      def setupUi(self, MainWindow):
          # ...
  
  
  class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
      def __init__(self, parent=None):
          super().__init__(parent)
          self.setupUi(self)
          self.generate.clicked.connect(self.generate_table)
          self.coordsToCheck = []
          self.tables = []
  
      def generate_table(self):
  
          try:
              size = int(self.size.text())
          except ValueError as e:
              print("error", e)
          else:
              tableWidget = QtWidgets.QTableWidget()
              tableWidget.setColumnCount(size)
              tableWidget.setRowCount(size)
              tableWidget.show()
              tableWidget.clicked.connect(self.on_clicked)
              self.tables.append(tableWidget)
  
      @QtCore.pyqtSlot(QtCore.QModelIndex)
      def on_clicked(self, index):
          tableWidget = self.sender()
          row, col = index.row(), index.column()
          tableWidget.model().setData(
              index, QtGui.QColor(216, 191, 216), QtCore.Qt.BackgroundRole
          )
          if (row, col) not in self.coordsToCheck:
              self.coordsToCheck.append((row, col))
          tableWidget.clearSelection()
  
  
  if __name__ == "__main__":
      import sys
  
      app = QtWidgets.QApplication(sys.argv)
      w = MainWindow()
      w.show()
      sys.exit(app.exec_())
  

---

更新：

如果要检测右键单击，则必须创建信号而不是直接调用方法：

class TableWidget(QtWidgets.QTableWidget):
    rightClicked = QtCore.pyqtSignal(QtCore.QModelIndex)

    def mouseReleaseEvent(self, event):
        super().mouseReleaseEvent(event)
        if event.button() == QtCore.Qt.RightButton:
            self.rightClicked.emit(self.indexAt(event.pos()))

def generate_table(self):
    try:
        size = int(self.size.text())
    except ValueError as e:
        print("error", e)
    else:
        tableWidget = TableWidget(size, size)
        tableWidget.show()
        tableWidget.clicked.connect(self.on_left_clicked)
        tableWidget.rightClicked.connect(self.on_right_clicked)
        self.tables.append(tableWidget)

@QtCore.pyqtSlot(QtCore.QModelIndex)
def on_left_clicked(self, index):
    self.change_color(self.sender(), index, QtGui.QColor(216, 191, 216))

@QtCore.pyqtSlot(QtCore.QModelIndex)
def on_right_clicked(self, index):
    self.change_color(self.sender(), index, None)

def change_color(self, view, index, color):
    if not isinstance(view, QtWidgets.QAbstractItemView):
        return
    model = view.model()
    if model is None:
        return
    model.setData(index, color, QtCore.Qt.BackgroundRole)
    view.clearSelection()