python - 尝试 Catch 块在 QCompleter for pyqt5 中未捕获异常

Question

我有一个 qcompleter 设置，以便在突出显示建议时填充两个不同的 lineEdits。当用户使用箭头遍历建议并超出范围时，会引发索引错误。例如，如果完成者给出了一个建议，但用户点击了两次向下箭头，则所选建议超出范围并引发异常。错误是我将它包围在 try except 块中，但无论出于何种原因它都没有捕获异常。当用户试图越界时，是否可以强制突出显示的选择从索引 0 开始？

from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QCompleter


class Ui_MainWindow(object):

    def on_button(self, text):
        try:
            nameList = text.split(', ')
            self.lineEdit_2.setText(nameList[0])
            QtCore.QTimer.singleShot(0, lambda: self.lineEdit.setText(nameList[1]))

        except IndexError:
            print("Out of bounds")

    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(439, 254)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.lineEdit = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit.setGeometry(QtCore.QRect(20, 90, 180, 25))
        self.lineEdit.setObjectName("lineEdit")
        self.lineEdit_2 = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit_2.setGeometry(QtCore.QRect(240, 90, 180, 25))
        self.lineEdit_2.setObjectName("lineEdit_2")

        food = ["pizza, chikin", "chikin, pizza", "chikin, pizza pizza", "chikin, pizza", "fried, pizza"]

        completer = QCompleter(food)
        completer.setCaseSensitivity(QtCore.Qt.CaseInsensitive)
        completer.setFilterMode(QtCore.Qt.MatchContains)
        self.lineEdit.setCompleter(completer)

        try:

            completer.highlighted.connect(self.on_button)
            completer.activated.connect(self.on_button)

        except IndexError:
            print("Out of bounds")
        MainWindow.setCentralWidget(self.centralwidget)


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

回溯（最后一次调用）：文件“stack.py”，第 13 行，在 QtCore.QTimer.singleShot(0, lambda: self.lineEdit.setText(nameList[1])) IndexError: list index out of range

标签： pythonpyqt5

Answer 1

主要的不理解是，在try ... except块中，您有将功能连接到信号。不执行它们。

节省计时器使用的解决方案：

from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QCompleter


class Ui_MainWindow(object):

    def on_button(self, text):
        if text not in self.food:
            self.lineEdit_2.setText("")
            return
        nameList = text.split(', ')
        self.lineEdit_2.setText(nameList[0])
        QtCore.QTimer.singleShot(0, lambda: self.lineEdit.setText(nameList[1]))


    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(439, 254)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.lineEdit = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit.setGeometry(QtCore.QRect(20, 90, 180, 25))
        self.lineEdit.setObjectName("lineEdit")
        self.lineEdit_2 = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit_2.setGeometry(QtCore.QRect(240, 90, 180, 25))
        self.lineEdit_2.setObjectName("lineEdit_2")

        self.food = ["pizza, chikin", "chikin, pizza", "chikin, pizza pizza", "chikin, pizza", "fried, pizza"]

        completer = QCompleter(self.food)
        completer.setCaseSensitivity(QtCore.Qt.CaseInsensitive)
        completer.setFilterMode(QtCore.Qt.MatchContains)
        self.lineEdit.setCompleter(completer)

        try:

            completer.highlighted.connect(self.on_button)
            # completer.activated.connect(self.on_button)

        except IndexError:
            print("Out of bounds")
        MainWindow.setCentralWidget(self.centralwidget)


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())