How would I scroll down to a row in a DataTable?

[bphunter1972]

I'm writing a simulation viewer, of sorts (like gdb, but not that).
I have one widget that is a DataTable showing a list of instructions. On mount, we start at instruction 0.
I'm able to highlight the current instruction number, set breakpoints on instructions, and all that.
What I'd like is if somebody were to step to the 50th instruction, that the DataTable would scroll to make that place visible on the screen.

The only method I can think of would be to artificially press the "Down" key repeatedly (or "Up", perhaps). But, there's gotta be a better way.

Any ideas?

[davep]

I'd use the cursor_coirdinate reactive property to set the location of the cursor, something like this:

from random import randint

from textual.app        import App, ComposeResult
from textual.widgets    import Header, Footer, DataTable
from textual.coordinate import Coordinate

class CursorMoveApp( App[ None ] ):

    ROWS = 500

    def compose( self ) -> ComposeResult:
        yield Header()
        yield DataTable()
        yield Footer()

    def on_mount( self ) -> None:
        dt = self.query_one( DataTable )
        dt.focus()
        dt.add_columns( "Row", "Row * 10", "Row * 100", "Row * 1000" )
        dt.add_rows( [ (
            f"{n}",
            f"{n * 10}",
            f"{n * 100}",
            f"{n * 100}",
        ) for n in range( self.ROWS ) ] )
        self.set_interval( 0.5, self.move_cursor )

    def move_cursor( self ) -> None:
        self.query_one( DataTable ).cursor_coordinate = Coordinate(
            randint( 0, self.ROWS - 1 ),
            randint( 0, 3 )
        )

if __name__ == "__main__":
    CursorMoveApp().run()

However, at the moment, the "viewing window" of the DataTable doesn't track where the cursor is when set that way. This is something we should tweak.

[davep]

For the sake of completeness, here's an variation on the above that will have the table move (it's now on our TODO list for DataTable to have this work with a public interface):

from random import randint

from textual.app        import App, ComposeResult
from textual.widgets    import Header, Footer, DataTable
from textual.coordinate import Coordinate

class CursorMoveApp( App[ None ] ):

    CSS = """
    DataTable {
        height: 1fr;
    }
    """

    ROWS = 500

    def compose( self ) -> ComposeResult:
        yield Header()
        yield DataTable()
        yield Footer()

    def on_mount( self ) -> None:
        dt = self.query_one( DataTable )
        dt.focus()
        dt.add_columns( "Row", "Row * 10", "Row * 100", "Row * 1000" )
        dt.add_rows( [ (
            f"{n}",
            f"{n * 10}",
            f"{n * 100}",
            f"{n * 100}",
        ) for n in range( self.ROWS ) ] )
        self.set_interval( 0.5, self.move_cursor )

    def move_cursor( self ) -> None:
        self.query_one( DataTable ).cursor_coordinate = Coordinate(
            randint( 0, self.ROWS - 1 ),
            randint( 0, 3 )
        )
        self.query_one( DataTable )._scroll_cursor_into_view(animate=True)

if __name__ == "__main__":
    CursorMoveApp().run()