如何使用 QListView 选择 QTableView 中显示哪些列

Question

假设我有以下数据框：

df = {'Banana': {0: 1, 1: 2, 2: 5}, 'Apple': {0: 3, 1: 4, 2: 3}, 'Elderberry': {0: 5, 1: 4, 2: 1},
'Clementine': {0: 4, 1: 7, 2: 0}, 'Fig': {0: 1, 1: 9, 2: 3}}

   Banana  Apple  Elderberry  Clementine  Fig
0       1      3           5           4    1
1       2      4           4           7    9
2       5      3           1           0    3

传递给QAbstractTableModel并与QTableView一起显示：

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.Qt import Qt
import pandas as pd


class MainWindow(QtWidgets.QMainWindow):

    def __init__(self, model):
        super().__init__()
        self.model = model
        self.table = QtWidgets.QTableView()
        self.table.setModel(self.model)
        self.setCentralWidget(self.table)


class TableModel(QtCore.QAbstractTableModel):

    def __init__(self, data):
        super(TableModel, self).__init__()
        self._data = data

    def rowCount(self, index):
        return self._data.shape[0]

    def columnCount(self, index):
        return self._data.shape[1]

    def headerData(self, section, orientation, role):
        # section is the index of the column/row.
        if role == Qt.DisplayRole:
            if orientation == Qt.Horizontal:
                return str(self._data.columns[section])

            if orientation == Qt.Vertical:
                return str(self._data.index[section])

    def data(self, index, role):

        row = index.row()
        column = index.column()
        column_name = self._data.columns[column]
        value = self._data.iloc[row, column]

        if role == Qt.DisplayRole:
            print(str(value))
            return str(value)


app = QtWidgets.QApplication(sys.argv)
df = {'Banana': {0: 1, 1: 2, 2: 5}, 'Apple': {0: 3, 1: 4, 2: 3}, 'Elderberry': {0: 5, 1: 4, 2: 1}, 'Clementine': {0: 4, 1: 7, 2: 0}, 'Fig': {0: 1, 1: 9, 2: 3}}
data_model = TableModel(df)
window1 = MainWindow(data_model)
window1.resize(800, 400)
window1.show()
sys.exit(app.exec_())

我现在想使用QListView 创建一个单独的窗口，以显示df 列名的列表，允许我指定要在上面的QTableView 中出现的列。 Like this：

如果我取消选中 QListView 中的列，我希望从 QTableView 中删除该列。同样，如果我检查一列，则该列应添加到表视图中。列表视图的目的本质上是允许用户指定哪些列应该出现在表格中。

这样做的最佳方法是什么？我想我可以创建一个QListWidget 并使用信号来更新QTableView。但是我有点不愿意这样做，因为我想它会变得非常混乱。

因此最佳做法是使用QListView，以便两个小部件引用相同的数据模型，并自动talk to each other like this？

Answer 1

您必须使用代理模型为列表视图构建模型（转置原始模型，将标题映射到单行或列并添加复选框）和另一个过滤：

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
import pandas as pd


class TableModel(QtCore.QAbstractTableModel):
    def __init__(self, data, parent=None):
        super(TableModel, self).__init__(parent)
        self._data = data

    def rowCount(self, index):
        return self._data.shape[0]

    def columnCount(self, index):
        return self._data.shape[1]

    def headerData(self, section, orientation, role):
        if role == QtCore.Qt.DisplayRole:
            if orientation == QtCore.Qt.Horizontal:
                return str(self._data.columns[section])
            if orientation == QtCore.Qt.Vertical:
                return str(self._data.index[section])

    def data(self, index, role):
        row = index.row()
        column = index.column()
        value = self._data.iloc[row, column]
        if role == QtCore.Qt.DisplayRole:
            return str(value)


class CustomProxy(QtCore.QSortFilterProxyModel):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.show_columns = set()

    def show_column(self, c):
        self.show_columns.add(c)
        self.invalidateFilter()

    def hide_column(self, c):
        if c not in self.show_columns:
            return
        self.show_columns.remove(c)
        self.invalidateFilter()

    def filterAcceptsColumn(self, source_column, source_parent):
        return source_column in self.show_columns


class HeaderProxyModel(QtCore.QIdentityProxyModel):
    checked = QtCore.pyqtSignal(int, bool)

    def __init__(self, parent=None):
        super().__init__(parent)
        self.checks = {}

    def columnCount(self, index=QtCore.QModelIndex()):
        return 1

    def data(self, index, role=QtCore.Qt.DisplayRole):
        if role == QtCore.Qt.DisplayRole:
            return self.headerData(index.row(), QtCore.Qt.Vertical, role)
        elif role == QtCore.Qt.CheckStateRole and index.column() == 0:
            return self.checks.get(
                QtCore.QPersistentModelIndex(index), QtCore.Qt.Unchecked
            )

    def setData(self, index, value, role=QtCore.Qt.EditRole):

        if not index.isValid():
            return False
        if role == QtCore.Qt.CheckStateRole:
            self.checks[QtCore.QPersistentModelIndex(index)] = value
            self.checked.emit(index.row(), bool(value))
            return True
        return False

    def flags(self, index):
        fl = super().flags(index)
        if index.column() == 0:
            fl |= QtCore.Qt.ItemIsEditable | QtCore.Qt.ItemIsUserCheckable
        return fl


class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, model):
        super().__init__()
        self.model = model

        self.listview = QtWidgets.QListView()
        tranpose = QtCore.QTransposeProxyModel()
        tranpose.setSourceModel(self.model)
        header_model = HeaderProxyModel()
        header_model.setSourceModel(tranpose)
        self.listview.setModel(header_model)

        self.tableview = QtWidgets.QTableView()
        self.filter_proxy = CustomProxy()
        self.filter_proxy.setSourceModel(self.model)
        self.tableview.setModel(self.filter_proxy)

        header_model.checked.connect(self.on_checked)

        central_widget = QtWidgets.QWidget()
        hlay = QtWidgets.QHBoxLayout(central_widget)
        hlay.addWidget(self.listview)
        hlay.addWidget(self.tableview, stretch=1)
        self.setCentralWidget(central_widget)

    def on_checked(self, r, state):
        if state:
            self.filter_proxy.show_column(r)
        else:
            self.filter_proxy.hide_column(r)


if __name__ == "__main__":

    app = QtWidgets.QApplication(sys.argv)
    df = pd.DataFrame(
        {
            "Banana": {0: 1, 1: 2, 2: 5},
            "Apple": {0: 3, 1: 4, 2: 3},
            "Elderberry": {0: 5, 1: 4, 2: 1},
            "Clementine": {0: 4, 1: 7, 2: 0},
            "Fig": {0: 1, 1: 9, 2: 3},
        }
    )
    data_model = TableModel(df)
    window1 = MainWindow(data_model)
    window1.resize(800, 400)
    window1.show()
    sys.exit(app.exec_())