i can't move cursor by press up/down and left/right arrow

[zhajio1988]

from textual.app import App, ComposeResult
from textual.widgets import DataTable

ROWS = [
    ("lane", "swimmer", "country", "time"),
    (4, "Joseph Schooling", "Singapore", 50.39),
    (2, "Michael Phelps", "United States", 51.14),
    (5, "Chad le Clos", "South Africa", 51.14),
    (6, "László Cseh", "Hungary", 51.14),
    (3, "Li Zhuhao", "China", 51.26),
    (8, "Mehdy Metella", "France", 51.58),
    (7, "Tom Shields", "United States", 51.73),
    (1, "Aleksandr Sadovnikov", "Russia", 51.84),
    (10, "Darren Burns", "Scotland", 51.84),
]


class TableApp(App):
    def compose(self) -> ComposeResult:
        yield DataTable()

    def on_mount(self) -> None:
        table = self.query_one(DataTable)
        table.add_columns(*ROWS[0])
        table.add_rows(ROWS[1:])


app = TableApp()
if __name__ == "__main__":
    app.run()

Above code is data_table example, i find i can't move cursor by press up/down and left/right arrow, i don't know why? Could you help solve it?

[davep]

Are you sure the DataTable had focus? By default, when a Textual application starts up, no widget will have focus, and so in this case the DataTable won't receive keyboard input. If you were to press Tab first and then use the cursor keys you should find that it works (testing here that's exactly what I see with your code above).

To make it so you don't have to press Tab first you could add the following to the end of your on_mount method:

table.focus()

[zhajio1988]

Cool，it works. Due to time constraints, I quickly looked for examples at https://textual.textualize.io/widgets/data_table to run down, I did not notice the need to press the tab key to work, thank you!

[davep]

Yup, it's not always obvious. As I say, right now, it's the startup state for Textual apps, and often a reason why it's a good idea to have some sort of styling for parts of your application that show where focus us.

There's a very good chance we'll change this soon so it's less confusing.