Module data_view 

Data view widget.

The DataView! widget can be used to dynamically presents data from a variable, unlike the widget::node::presenter node the generated UI can be retained across updates of the data variable.

The example below declares a DataView! using the shorthand syntax:

use zng::prelude::*;

fn countdown(n: impl IntoVar<usize>) -> UiNode {
    DataView!(::<usize>, n, hn!(|a| {
        // we generate a new view on the first call or when the data has changed to zero.
        if a.view_is_nil() || a.data().get_new() == Some(0) {
            a.set_view(if a.data().get() > 0 {
                // countdown view
                Text! {
                    font_size = 28;
                    // bind data, same view will be used for all n > 0 values.
                    txt = a.data().map_to_txt();
                }
            } else {
                // finished view
                Text! {
                    font_color = rgb(0, 128, 0);
                    font_size = 18;
                    txt = "Congratulations!";
                }
            });
        }
    }))
}

You can also use the normal widget syntax and set the view property.

DataView! {
    view::<usize> = {
        data: n,
        update: hn!(|a| {}),
    };
}

Full API

See zng_wgt_data_view for the full view API.

Structs

DataView

W Dynamically presents a data variable.

DataViewArgs

Arguments for the DataView! widget.