python - PyQt5 QML TreeView 示例

Question

我尝试使用 PyQt5.6 (Python 3.4) 和 QML 设置一个简单的 TreeView 示例。我只是找到了一些 C++ 示例，但没有与 PyQt 相关的内容。我选择了与 PyQt 源一起的 simpletreemodel 示例并对其进行了修改( https://github.com/baoboa/pyqt5/tree/master/examples/itemviews/simpletreemodel )。

模型很可能有问题。我收到两条错误消息:

simpletreemodel.qml:13:5:QML TreeView:检测到属性“model”的绑定(bind)循环

...qt/5.6/gcc_64/qml/QtQuick/Controls/TreeView.qml:94:16:无法将[未定义]分配给 QAbstractItemModel*

知道发生了什么和/或出了什么问题吗？ qml TreeView 刚刚在 Qt 5.5 中引入，也许它在 PyQt 中不能完全工作？!没有找到任何相关信息。

这是我的代码:

simpletreemodel.qml

import QtQuick 2.5
import QtQuick.Controls 1.4
import QtQml.Models 2.2

Rectangle {
    width: 480
    height: 640

    TreeView {
        id: treeView
        anchors.fill: parent
        anchors.margins: 6
        anchors.top: parent.top
        anchors.horizontalCenter: parent.horizontalCenter

        model: model

        TableViewColumn {
            title: "Title"
            role: "TitleRole"
            resizable: true
        }

        TableViewColumn {
            title: "Summary"
            role: "SummaryRole"
            resizable: true
        }
    }
}

简单树模型.py

#!/usr/bin/env python

from PyQt5.QtCore import (
    QAbstractItemModel, QFile,
    QIODevice, QModelIndex, Qt,
    QUrl
)
from PyQt5.QtGui import QGuiApplication
from PyQt5.QtQuick import QQuickView

import simpletreemodel_rc

class TreeItem(object):
    def __init__(self, data, parent=None):
        self.parentItem = parent
        self.itemData = data
        self.childItems = []

    def appendChild(self, item):
        self.childItems.append(item)

    def child(self, row):
        return self.childItems[row]

    def childCount(self):
        return len(self.childItems)

    def columnCount(self):
        return len(self.itemData)

    def data(self, column):
        try:
            return self.itemData[column]
        except IndexError:
            return None

    def parent(self):
        return self.parentItem

    def row(self):
        if self.parentItem:
            return self.parentItem.childItems.index(self)

        return 0


class TreeModel(QAbstractItemModel):
    def __init__(self, data, parent=None):
        super(TreeModel, self).__init__(parent)

        self.rootItem = TreeItem(("Title", "Summary"))
        self.setupModelData(data.split('\n'), self.rootItem)

    def roleNames(self):
        roles = {
            Qt.UserRole + 1: b"TitleRole",
            Qt.UserRole + 2: b"SummaryRole"
        }
        return roles

    def columnCount(self, parent):
        if parent.isValid():
            return parent.internalPointer().columnCount()
        else:
            return self.rootItem.columnCount()

    def data(self, index, role):
        if not index.isValid():
            return None

        if role != Qt.DisplayRole:
            return None

        item = index.internalPointer()

        return item.data(index.column())

    def flags(self, index):
        if not index.isValid():
            return Qt.NoItemFlags

        return Qt.ItemIsEnabled | Qt.ItemIsSelectable

    def headerData(self, section, orientation, role):
        if orientation == Qt.Horizontal and role == Qt.DisplayRole:
            return self.rootItem.data(section)

        return None

    def index(self, row, column, parent):
        if not self.hasIndex(row, column, parent):
            return QModelIndex()

        if not parent.isValid():
            parentItem = self.rootItem
        else:
            parentItem = parent.internalPointer()

        childItem = parentItem.child(row)
        if childItem:
            return self.createIndex(row, column, childItem)
        else:
            return QModelIndex()

    def parent(self, index):
        if not index.isValid():
            return QModelIndex()

        childItem = index.internalPointer()
        parentItem = childItem.parent()

        if parentItem == self.rootItem:
            return QModelIndex()

        return self.createIndex(parentItem.row(), 0, parentItem)

    def rowCount(self, parent):
        if parent.column() > 0:
            return 0

        if not parent.isValid():
            parentItem = self.rootItem
        else:
            parentItem = parent.internalPointer()

        return parentItem.childCount()

    def setupModelData(self, lines, parent):
        parents = [parent]
        indentations = [0]

        number = 0

        while number < len(lines):
            position = 0
            while position < len(lines[number]):
                if lines[number][position] != ' ':
                    break
                position += 1

            lineData = lines[number][position:].trimmed()

            if lineData:
                # Read the column data from the rest of the line.
                columnData = [s for s in lineData.split('\t') if s]

                if position > indentations[-1]:
                    # The last child of the current parent is now the new
                    # parent unless the current parent has no children.

                    if parents[-1].childCount() > 0:
                        parents.append(parents[-1].child(parents[-1].childCount() - 1))
                        indentations.append(position)

                else:
                    while position < indentations[-1] and len(parents) > 0:
                        parents.pop()
                        indentations.pop()

                # Append a new item to the current parent's list of children.
                parents[-1].appendChild(TreeItem(columnData, parents[-1]))

            number += 1


if __name__ == '__main__':
    import sys

    app = QGuiApplication(sys.argv)
    view = QQuickView() 

    f = QFile(':/default.txt')
    f.open(QIODevice.ReadOnly)
    model = TreeModel(f.readAll())
    f.close()

    root_context = view.rootContext().setContextProperty('model', model)
    view.setSource(QUrl.fromLocalFile('simpletreemodel.qml'))
    view.show()
    sys.exit(app.exec_())

Answer 1

root_context = view.rootContext().setContextProperty('model', model)

不要使用model作为模型名称。