Adding QgsLayoutItemTextTable to Print Layout

Question

I am writing a script that automatically generates a print layout. In addition to the map, the print layout should contain a table with results of a series of calculations that I have in the form of a python dictionary. While I have gotten into the workflow of adding layout items to the print layout, QgsLayoutItemTextTable seems to work differently.

This works fine:

project = QgsProject.instance()
layout = QgsPrintLayout(project)
layout.initializeDefaults()

title = QgsLayoutItemLabel(layout)
title.setText('MyTitle')
title.adjustSizeToText()
layout.addLayoutItem(title)

The QgsLayoutItemTextTable class, however, is for some reason not based on the QgsLayoutItem class and therefore

project = QgsProject.instance()
layout = QgsPrintLayout(project)
layout.initializeDefaults()

table = QgsLayoutItemTextTable(layout)
table.addRow(['hello', 'world', '!'])
layout.addLayoutItem(table)

results in the following error:

TypeError: QgsLayout.addLayoutItem(): argument 1 has unexpected type 'QgsLayoutItemTextTable'

Can anyone explain to me why this is the case and what is the intended workflow?

Answer 1

In this case to add a table the method is not the same. You need add using this addMultiFrame() because QgsLayoutItemTextTable inherits from QgsLayoutMultiFrame:

layout.addMultiFrame(table)

Minimum sample:

project = QgsProject.instance()
layout = QgsPrintLayout(project)
layout.initializeDefaults()

table = QgsLayoutItemTextTable(layout)
layout.addMultiFrame(table)

# Add columns       
cols = [QgsLayoutTableColumn(),QgsLayoutTableColumn(),QgsLayoutTableColumn()]
cols[0].setHeading("heading 0")
cols[1].setHeading("heading 1")
cols[2].setHeading("heading 2")
table.setColumns(cols)

# Add only 1 row
table.setContents([['hello', 'world', '!']])

# Base class for frame items, which form a layout multiframe item.
frame = QgsLayoutFrame(layout, table)
frame.attemptResize(QgsLayoutSize(30, 30), True)
table.addFrame(frame)