Error while opening qpt layout file

Question

I want to save my layout. I've tried this solution but and it worked. The file is created but when I try to open it, it doesn't work. I don't know why.

Here is my code:

project = QgsProject.instance()
manager = project.layoutManager() 
layout = QgsPrintLayout(project)
layout.initializeDefaults()
layout.setName(layoutName)
manager.addLayout(layout)
pc = layout.pageCollection()
page = pc.pages()[0]
page.setPageSize(pageSize, QgsLayoutItemPage.Orientation.Landscape)
layout_view = open_designer.view()
layout.saveAsTemplate('C:/Users/ilyasse2.0/Desktop/SQRLAND/layout.qpt',QgsReadWriteContext())

The error I get is :

Invalid Data Source: C:\Users\ilyasse2.0\Desktop\SQRLAND\layout.qpt is not a valid or recognized data source.

Answer 1

I've tried your first code and got some issues. An edited version below

pageSize = "A4"
layoutName = 'whatever'

project = QgsProject.instance()
manager = project.layoutManager() 
layout = QgsPrintLayout(project)
layout.initializeDefaults()
layout.setName(layoutName)
manager.addLayout(layout)
pc = layout.pageCollection()
page = pc.pages()[0]
page.setPageSize(pageSize, QgsLayoutItemPage.Landscape) # Changed here
# Path changed because Linux (keep your own path for Windows)
layout.saveAsTemplate('/tmp/layout.qpt', QgsReadWriteContext())

Then, I'm able to load the qpt file. What version of QGIS are your using? How do you proceed to load the qpt file?