Thank you, @ccc and @cvp for the helpful replies. I reviewed the reference @cvp suggested and it clear that NavigationView isn't the best tool for what I want to do: a program that displays the chords and lyrics from ChordPro files with the correct formatting and autoscrolling, including a scrollable list of the .chordpro files and a scrollable list of songs they contain.

I was able to repurpose a single TableView to handle all of this, which saved me from the complexity of working with NavigationView. I plan to try out the script in a guitar jam next month.

Thank you, @ccc and @cvp for the helpful replies. I reviewed the reference @cvp suggested and it clear that NavigationView isn't the best tool for what I want to do: a program that displays the chords and lyrics from ChordPro files with the correct formatting and autoscrolling, including a scrollable list of the .chordpro files and a scrollable list of songs they contain.

I was able to repurpose a single TableView to handle all of this, which saved me from the complexity of working with NavigationView. I plan to try out the script in a guitar jam next month.

I am unable to use button actions on a table view, all within a subview using NavigationView. I would like to be able to click a button on the subview and have it manipulate the table view, but even trying to print the contents of objects in the subview isn't working, as shown below. I expect I am simply referencing the variables the wrong way, but I have not been able to get through this impasse. I get errors shown as comments in the code below.

To create the example below, I use two pyui files which I have summarized. If there is a way to share the pyui files in the forum, let me know. I tried embedding the json for the pyui as a string, but that didn't work. And I am sorry the example code is so complicated. I am happy to provide clarification.

import ui

# rootView.pyui contents:
# Text Field: name = displayString, action = none
# Button: name = displayButton, action = self.bt_display
# Table View: name = rootviewListTable

# subView.pyui contents:
# Text Field: name = svDisplayString, action = none
# Button: name = svDisplayButton, action = self.bt_svDisplay
# Button: name = attributesButton, action = self.bt_attributes
# Table View: name = svText

def make_button_item(action, image_name):
    return ui.ButtonItem(action=action, image=ui.Image.named(image_name))

class navviewManager(ui.View):

        def __init__(self):
                self.currentSongTitle = ""
                self.root_view = ui.load_view("rootView.pyui")
                self.root_view.left_button_items = [
                        make_button_item(self.bt_close, "ionicons-close-24")
                ]
                self.root_view.right_button_items = [
                        make_button_item(self.bt_subview, "ionicons-arrow-right-b-24")
                ]
                self.nav_view = ui.NavigationView(self.root_view)
                self.nav_view.present(hide_title_bar=True)
                
        def bt_subview(self, sender):
                sub_view = load_view("subView.pyui")
                sub_view.name = "subview"
                myText = "This is myText"
                myList = ui.ListDataSource(myText)
                myTextTable= sub_view["svText"]
                myTextTable.data_source = myTextTable.delegate = myList
                myTextTable.data_source.delete_enabled = myTextTable.editing = False
                self.nav_view.push_view(sub_view)

        def bt_display(self, sender):
                displayTerm = self.root_view["displayString"].text
                myList = ui.ListDataSource(displayTerm)
                
                myRootListTable = self.root_view["rootviewListTable"]
                myRootListTable.data_source = myRootListTable.delegate = myList
                myRootListTable.data_source.delete_enabled = myRootListTable.editing = False
                myRootListTable.reload_data()
                
        def bt_svDisplay(self, sender):
                svDisplayTerm = self.nav_view["svDisplayString"].text
                # AttributeError: 'NoneType' object has no attribute 'text'
                myList = ui.ListDataSource(svDisplayTerm)
                
                svListTable = self.nav_view["svText"]
                svListTable.data_source = svListTable.delegate = myList
                svListTable.data_source.delete_enabled = svListTable.editing = False
                svListTable.reload_data()
        
        def bt_attributes(self, sender):
                print(self.root_view["displayString"].text)  # OK
                print(vars(self.root_view["displayString"])) # OK
                print(vars(self.nav_view["svDisplayString"]))
                # TypeError: vars() argument must have __dict__ attribute

        def bt_close(self, sender):
            self.nav_view.close()
                         
manager = navviewManager()

@cvp Thank you. My program works now. Next time I will try the in-forum Search function rather that rely on an Internet search engine.

My first posting. I am unable to use NavigationView in full_screen mode. Any guidance would be appreciated. Here is an example where I have changed the .present argument from hide_title_bar=True to 'full_screen' from an on-line example found here. Despite specifying full_screen, it still appears as an overlay in the middle portion of my screen.

-Seriph

import ui


def make_button_item(action, image_name):
    return ui.ButtonItem(action=action, image=ui.Image.named(image_name))


class NavView(ui.View):
    def __init__(self):
        root_view = ui.load_view()
        root_view.left_button_items = [
            make_button_item(self.bt_close, "ionicons-close-24")
        ]
        root_view.right_button_items = [
            make_button_item(self.bt_subview, "ionicons-arrow-right-b-24")
        ]
        self.nav_view = ui.NavigationView(root_view)
        self.nav_view.present('full_screen') # hide_title_bar=True)
        
    def bt_subview(self, sender):
        sub_view = ui.load_view("switchview1.pyui")
        sub_view.name = "subview"
        sub_view["btn_Okay"].action = self.bt_action
        sub_view["btn_Cancel"].action = self.bt_action
        self.nav_view.push_view(sub_view)

    def bt_close(self, sender):
        self.nav_view.close()

    def bt_action(self, sender):
        print("action from " + sender.name)


NavView()