QgsAttributeTableView shows nothing in my QGIS plugin

Question

I have created a plugin using the Plugin Builder plugin, and I tried to adapt it to show a QgsAttributeTable (by following this example). I get absolutely no errors or warnings, but it simply shows an empty white box. Do you have any suggestions for what I should try?

class FooDockWidget(QtWidgets.QDockWidget):
    def __init__(self, parent=None):

        super().__init__(parent)
        self.setWindowTitle('This_is_the_window_title!!!')

        widget = QWidget(self)
        self.setWidget(widget)

        layout = QVBoxLayout(widget)
        widget.setLayout(layout)

        layer = iface.activeLayer()
        assert layer is not None

        canvas = iface.mapCanvas()
        vector_layer_cache = QgsVectorLayerCache(layer, 10000)
        attribute_table_model = QgsAttributeTableModel(vector_layer_cache)
        attribute_table_model.loadLayer()

        attribute_table_filter_model = QgsAttributeTableFilterModel(canvas, attribute_table_model)
        attribute_table_view = QgsAttributeTableView()
        attribute_table_view.setModel(attribute_table_filter_model)

        layout.addWidget(attribute_table_view)

Answer 1

Your class lacks of self, so, at the end of the instantiation (= end of the __init__), the references of the objects without self not binded in other objects of the class are destroyed, so not displayed.

Correct the end of your __init__ with :

        self.canvas = iface.mapCanvas()
        self.vector_layer_cache = QgsVectorLayerCache(layer, 10000)
        self.attribute_table_model = QgsAttributeTableModel(self.vector_layer_cache)
        self.attribute_table_model.loadLayer()

        self.attribute_table_filter_model = QgsAttributeTableFilterModel(self.canvas, self.attribute_table_model)
        self.attribute_table_view = QgsAttributeTableView()
        self.attribute_table_view.setModel(self.attribute_table_filter_model)

        layout.addWidget(self.attribute_table_view)