Fix the modelview programming tutorial

Add some documentation examples and snippets to fix most outstanding
C++ to Python conversion errors.

The rest looks roughly ok and could be improved by further fixing up
the snippet conversion.

Task-number: PYSIDE-1984
Pick-to: 6.3 6.2
Change-Id: I8c1bdcbc4a07847b2731ef7e2b9ba666cc00ccd6
Reviewed-by: Christian Tismer <tismer@stackless.com>

5 files changed, 347 insertions, 0 deletions

diff --git a/sources/pyside6/doc/snippets/qtbase/examples/widgets/itemviews/spinboxdelegate/delegate_0.h.py b/sources/pyside6/doc/snippets/qtbase/examples/widgets/itemviews/spinboxdelegate/delegate_0.h.py
new file mode 100644
index 000000000..de386a5ac
--- /dev/null
+++ b/sources/pyside6/doc/snippets/qtbase/examples/widgets/itemviews/spinboxdelegate/delegate_0.h.py
@@ -0,0 +1,18 @@
+class SpinBoxDelegate(QStyledItemDelegate):
+    """A delegate that allows the user to change integer values from the model
+       using a spin box widget. """
+
+    def __init__(self, parent=None):
+        ...
+
+    def createEditor(self, parent, option, index):
+        ...
+
+    def setEditorData(self, editor, index):
+        ...
+
+    def setModelData(self, editor, model, index):
+        ...
+
+    def updateEditorGeometry(self, editor, option, index):
+        ...
diff --git a/sources/pyside6/doc/snippets/qtbase/src/widgets/doc/snippets/stringlistmodel/model_0.h.py b/sources/pyside6/doc/snippets/qtbase/src/widgets/doc/snippets/stringlistmodel/model_0.h.py
new file mode 100644
index 000000000..02a02aaf8
--- /dev/null
+++ b/sources/pyside6/doc/snippets/qtbase/src/widgets/doc/snippets/stringlistmodel/model_0.h.py
@@ -0,0 +1,24 @@
+class StringListModel(QAbstractListModel):
+    def __init__(self, strings, parent=None):
+        ...
+
+    def rowCount(self, parent=QModelIndex()):
+        ...
+
+    def data(self, index, role):
+        ...
+
+    def headerData(self, section, orientation, role=Qt.DisplayRole):
+        ...
+
+    def flags(self, index):
+        ...
+
+    def setData(self, index, value, role=Qt.EditRole):
+        ...
+
+    def insertRows(self, position, rows, parent):
+        ...
+
+    def removeRows(self, position, rows, parent):
+        ...
diff --git a/sources/pyside6/doc/tutorials/modelviewprogramming/qlistview-dnd.py b/sources/pyside6/doc/tutorials/modelviewprogramming/qlistview-dnd.py
new file mode 100644
index 000000000..3a37cc0f3
--- /dev/null
+++ b/sources/pyside6/doc/tutorials/modelviewprogramming/qlistview-dnd.py
@@ -0,0 +1,137 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+import sys
+
+from PySide6.QtWidgets import (QAbstractItemView, QApplication, QMainWindow,
+                               QListView)
+from PySide6.QtCore import (QByteArray, QDataStream, QIODevice, QMimeData,
+                            QModelIndex, QStringListModel, Qt)
+
+
+class DragDropListModel(QStringListModel):
+    """A simple model that uses a QStringList as its data source."""
+
+    def __init__(self, strings, parent=None):
+          super().__init__(strings, parent)
+
+#! [0]
+
+    def canDropMimeData(self, data, action, row, column, parent):
+        if not data.hasFormat("application/vnd.text.list"):
+            return False
+
+        if column > 0:
+            return False
+
+        return True
+#! [0]
+#! [1]
+    def dropMimeData(self, data, action, row, column, parent):
+        if not self.canDropMimeData(data, action, row, column, parent):
+            return False
+
+        if action == Qt.IgnoreAction:
+            return True
+#! [1]
+
+#! [2]
+        begin_row = 0
+
+        if row != -1:
+            begin_row = row
+#! [2] #! [3]
+        elif parent.isValid():
+            begin_row = parent.row()
+#! [3] #! [4]
+        else:
+            begin_row = self.rowCount(QModelIndex())
+#! [4]
+
+#! [5]
+        encoded_data = data.data("application/vnd.text.list")
+        stream = QDataStream(encoded_data, QIODevice.ReadOnly)
+        new_items = []
+        while not stream.atEnd():
+            new_items.append(stream.readQString())
+#! [5]
+
+#! [6]
+        self.insertRows(begin_row, len(new_items), QModelIndex())
+        for text in new_items:
+            idx = self.index(begin_row, 0, QModelIndex())
+            self.setData(idx, text)
+            begin_row += 1
+
+        return True
+#! [6]
+
+#! [7]
+    def flags(self, index):
+        default_flags = super().flags(index)
+        if index.isValid():
+            return Qt.ItemIsDragEnabled | Qt.ItemIsDropEnabled | default_flags
+        return Qt.ItemIsDropEnabled | default_flags
+#! [7]
+
+#! [8]
+    def mimeData(self, indexes):
+        mime_data = QMimeData()
+        encoded_data = QByteArray()
+        stream = QDataStream(encoded_data, QIODevice.WriteOnly)
+        for index in indexes:
+            if index.isValid():
+                text = self.data(index, Qt.DisplayRole)
+                stream.writeQString(text)
+
+        mime_data.setData("application/vnd.text.list", encoded_data)
+        return mime_data
+#! [8]
+
+#! [9]
+    def mimeTypes(self):
+        return ["application/vnd.text.list"]
+#! [9]
+
+#! [10]
+    def supportedDropActions(self):
+        return Qt.CopyAction | Qt.MoveAction
+#! [10]
+
+
+class MainWindow(QMainWindow):
+
+    def __init__(self, parent=None):
+        super().__init__(parent)
+
+        file_menu = self.menuBar().addMenu("&File")
+        quit_action = file_menu.addAction("E&xit")
+        quit_action.setShortcut("Ctrl+Q")
+
+#! [mainwindow0]
+        self._list_view = QListView(self)
+        self._list_view.setSelectionMode(QAbstractItemView.ExtendedSelection)
+        self._list_view.setDragEnabled(True)
+        self._list_view.setAcceptDrops(True)
+        self._list_view.setDropIndicatorShown(True)
+#! [mainwindow0]
+
+        quit_action.triggered.connect(self.close)
+
+        self.setup_list_items()
+
+        self.setCentralWidget(self._list_view)
+        self.setWindowTitle("List View")
+
+    def setup_list_items(self):
+        items = ["Oak", "Fir", "Pine", "Birch", "Hazel", "Redwood", "Sycamore",
+                 "Chestnut", "Mahogany"]
+        model = DragDropListModel(items, self)
+        self._list_view.setModel(model)
+
+
+if __name__ == '__main__':
+    app = QApplication(sys.argv)
+    window = MainWindow()
+    window.show()
+    sys.exit(app.exec())
diff --git a/sources/pyside6/doc/tutorials/modelviewprogramming/simplemodel-use.py b/sources/pyside6/doc/tutorials/modelviewprogramming/simplemodel-use.py
new file mode 100644
index 000000000..1bacfd829
--- /dev/null
+++ b/sources/pyside6/doc/tutorials/modelviewprogramming/simplemodel-use.py
@@ -0,0 +1,44 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+import sys
+
+from PySide6.QtWidgets import (QApplication, QFileSystemModel, QLabel,
+                               QVBoxLayout, QWidget)
+from PySide6.QtGui import QPalette
+from PySide6.QtCore import QDir, Qt
+
+
+if __name__ == '__main__':
+    app = QApplication(sys.argv)
+
+    window = QWidget()
+    layout = QVBoxLayout(window)
+    title = QLabel("Some items from the directory model", window)
+    title.setBackgroundRole(QPalette.Base)
+    title.setMargin(8)
+    layout.addWidget(title)
+
+#! [0]
+    model = QFileSystemModel()
+    model.setRootPath(QDir.currentPath())
+
+    def on_directory_loaded(directory):
+        parent_index = model.index(directory)
+        num_rows = model.rowCount(parent_index)
+#! [1]
+        for row in range(num_rows):
+            index = model.index(row, 0, parent_index)
+#! [1]
+#! [2]
+            text = model.data(index, Qt.DisplayRole)
+#! [2]
+            label = QLabel(text, window)
+            layout.addWidget(label)
+
+    model.directoryLoaded.connect(on_directory_loaded)
+#! [0]
+
+    window.setWindowTitle("A simple model example")
+    window.show()
+    sys.exit(app.exec())
diff --git a/sources/pyside6/doc/tutorials/modelviewprogramming/stringlistmodel.py b/sources/pyside6/doc/tutorials/modelviewprogramming/stringlistmodel.py
new file mode 100644
index 000000000..2c8493aa9
--- /dev/null
+++ b/sources/pyside6/doc/tutorials/modelviewprogramming/stringlistmodel.py
@@ -0,0 +1,124 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+import sys
+
+from PySide6.QtWidgets import (QApplication, QListView)
+from PySide6.QtCore import QAbstractListModel, QStringListModel, QModelIndex, Qt
+
+
+#! [0]
+class StringListModel(QAbstractListModel):
+    def __init__(self, strings, parent=None):
+        super().__init__(parent)
+        self._strings = strings
+
+#! [0]
+    def rowCount(self, parent=QModelIndex()):
+        """Returns the number of items in the string list as the number of rows
+           in the model."""
+        return len(self._strings)
+#! [0]
+
+#! [1]
+    def data(self, index, role):
+        """Returns an appropriate value for the requested data.
+           If the view requests an invalid index, an invalid variant is returned.
+           Any valid index that corresponds to a string in the list causes that
+          string to be returned."""
+        row = index.row()
+        if not index.isValid() or row >= len(self._strings):
+            return None
+        if role != Qt.DisplayRole and role != Qt.EditRole:
+            return None
+        return self._strings[row]
+#! [1]
+
+#! [2]
+    def headerData(self, section, orientation, role=Qt.DisplayRole):
+        """Returns the appropriate header string depending on the orientation of
+           the header and the section. If anything other than the display role is
+           requested, we return an invalid variant."""
+        if role != Qt.DisplayRole:
+            return None
+        if orientation == Qt.Horizontal:
+            return f"Column {section}"
+        return f"Row {section}"
+#! [2]
+
+#! [3]
+    def flags(self, index):
+        """Returns an appropriate value for the item's flags. Valid items are
+           enabled, selectable, and editable."""
+
+        if not index.isValid():
+            return Qt.ItemIsEnabled
+        return super().flags(index) | Qt.ItemIsEditable
+#! [3]
+
+    #! [4]
+    def setData(self, index, value, role=Qt.EditRole):
+        """Changes an item in the string list, but only if the following conditions
+           are met:
+
+           # The index supplied is valid.
+           # The index corresponds to an item to be shown in a view.
+           # The role associated with editing text is specified.
+
+           The dataChanged() signal is emitted if the item is changed."""
+
+        if index.isValid() and role == Qt.EditRole:
+            self._strings[index.row()] = value
+            self.dataChanged.emit(index, index, {role})
+            return True
+#! [4] #! [5]
+        return False
+#! [5]
+
+#! [6]
+    def insertRows(self, position, rows, parent):
+        """Inserts a number of rows into the model at the specified position."""
+        self.beginInsertRows(QModelIndex(), position, position + rows - 1)
+        for row in range(rows):
+            self._strings.insert(position, "")
+        self.endInsertRows()
+        return True
+#! [6] #! [7]
+#! [7]
+
+#! [8]
+    def removeRows(self, position, rows, parent):
+        """Removes a number of rows from the model at the specified position."""
+        self.beginRemoveRows(QModelIndex(), position, position + rows - 1)
+        for row in range(rows):
+            del self._strings[position]
+        self.endRemoveRows()
+        return True
+#! [8] #! [9]
+#! [9]
+
+
+#! [main0]
+if __name__ == '__main__':
+    app = QApplication(sys.argv)
+
+#! [main1]
+    numbers = ["One", "Two", "Three", "Four", "Five"]
+    model = StringListModel(numbers)
+#! [main0] #! [main1] #! [main2] #! [main3]
+    view = QListView()
+#! [main2]
+    view.setWindowTitle("View onto a string list model")
+#! [main4]
+    view.setModel(model)
+#! [main3] #! [main4]
+
+    model.insertRows(5, 7, QModelIndex())
+    for row in range(5, 12):
+        index = model.index(row, 0, QModelIndex())
+        model.setData(index, f"{row+1}")
+
+#! [main5]
+    view.show()
+    sys.exit(app.exec())
+#! [main5]