Module drag_drop 

Drag&drop service, types and events.

The example below defines a window that shows the current dragging data that has entered any of the app windows.

use zng::prelude::*;
use zng::drag_drop::*;

let data = var::<Vec<DragDropData>>(vec![]);
Window! {
    padding = 20;
    child = Container! {
        widget::border = 5, widget::BorderSides::dashed(colors::GRAY);
        widget::corner_radius = 15;
        child_align = Align::CENTER;
        on_drag_enter = hn!(data, |_| {
            data.set(DRAG_DROP.dragging_data().get());
        });
        on_drag_leave = hn!(data, |_| {
            data.set(vec![]);
        });
        on_drop = hn!(data, |args| {
            data.set(args.data.clone());
        });
        child = Text!(data.map(|d| if d.is_empty() {
            Txt::from("drag over to inspect")
        } else {
            formatx!("{d:#?}")
        }));
    };
}

Limitations

Drag&drop depends on the view-process backend, the default view-process (zng-view) is currently very limited:

• No drag start from the app.
• Only file path drops.
• No support in Wayland, you can work around by calling std::env::remove_var("WAYLAND_DISPLAY"); before zng::env::init!() in your main function, this enables XWayland that has support for the basic file path drop.
• In X11 and macOS there is no cursor position notification on hover, just on drop, DRAG_HOVERED_EVENT and DRAG_MOVE_EVENT based event properties will only fire once for the widget that is about to receive a drop.

Full API

See zng_ext_input::drag_drop and zng_wgt_input::drag_drop for the full drag&drop API.

Structs

DRAG_DROP

Drag & drop service.

DragDropEffect

Drag&drop drop effect on the data source.

DragEndArgs

Arguments for DRAG_END_EVENT.

DragHandle

Represents dragging data.

DragHoveredArgs

Arguments for DRAG_HOVERED_EVENT.

DragMoveArgs

DRAG_MOVE_EVENT arguments.

DragStartArgs

Arguments for DRAG_START_EVENT.

DropArgs

Arguments for DROP_EVENT.

WeakDragHandle

Weak DragHandle.

Enums

DragDropData

Drag&drop data payload.

Statics

DRAG_END_EVENT

Drag&drop gesture started from the draggable widget has ended.

DRAG_HOVERED_EVENT

Drag&drop enter or exit a drop target widget.

DRAG_MOVE_EVENT

Drag&drop is dragging over the target widget.

DRAG_START_EVENT

Drag&drop started dragging a draggable widget.

DROP_EVENT

Drag&drop action finished over some drop target widget.

Functions

draggable

P If this widget can be dragged in a drag&drop operation.

on_drag_end

P Draggable widget stopped dragging.

on_drag_enter

P Dragging cursor entered the widget area and the widget is enabled.

on_drag_hovered

P Dragging cursor entered or exited the widget area and the widget is enabled.

on_drag_leave

P Dragging cursor exited the widget area and the widget is enabled.

on_drag_start

P Draggable widget started dragging.

on_drop

P Dragging cursor dropped data in the widget area and the widget is enabled.

on_pre_drag_end

P Preview on_drag_end event.

on_pre_drag_enter

P Preview on_drag_enter event.

on_pre_drag_hovered

P Preview on_drag_hovered event.

on_pre_drag_leave

P Preview on_drag_leave event.

on_pre_drag_start

P Preview on_drag_start event.

on_pre_drop

P Preview on_drop event.