Add drag and drop to List View in Navigation Screen

packages/block-editor/src/components/block-draggable/draggable-chip.js

@@ -23,7 +23,7 @@ export default function BlockDraggableChip( { clientIds } ) {
 			const [ firstId ] = clientIds;
 			const blockName = getBlockName( firstId );
 
-			return getBlockType( blockName ).icon;
+			return getBlockType( blockName )?.icon;
 		},
 		[ clientIds ]
 	);

packages/block-editor/src/components/block-draggable/index.js

@@ -17,6 +17,7 @@ const BlockDraggable = ( {
 	cloneClassname,
 	onDragStart,
 	onDragEnd,
+	elementId,
 } ) => {
 	const { srcRootClientId, isDraggable } = useSelect(
 		( select ) => {
@@ -68,7 +69,7 @@ const BlockDraggable = ( {
 	return (
 		<Draggable
 			cloneClassname={ cloneClassname }
-			elementId={ `block-${ clientIds[ 0 ] }` }
+			elementId={ elementId || `block-${ clientIds[ 0 ] }` }
 			transferData={ transferData }
 			onDragStart={ ( event ) => {
 				startDraggingBlocks( clientIds );

packages/block-editor/src/components/block-navigation/appender.js

@@ -1,9 +1,15 @@
+/**
+ * External dependencies
+ */
+import classnames from 'classnames';
+
 /**
  * WordPress dependencies
  */
 import { __experimentalTreeGridCell as TreeGridCell } from '@wordpress/components';
 import { useInstanceId } from '@wordpress/compose';
 import { __, sprintf } from '@wordpress/i18n';
+import { useSelect } from '@wordpress/data';
 
 /**
  * Internal dependencies
@@ -20,6 +26,19 @@ export default function BlockNavigationAppender( {
 	terminatedLevels,
 	path,
 } ) {
+	const isDragging = useSelect(
+		( select ) => {
+			const { isBlockBeingDragged, isAncestorBeingDragged } = select(
+				'core/block-editor'
+			);
+
+			return (
+				isBlockBeingDragged( parentBlockClientId ) ||
+				isAncestorBeingDragged( parentBlockClientId )
+			);
+		},
+		[ parentBlockClientId ]
+	);
 	const instanceId = useInstanceId( BlockNavigationAppender );
 	const descriptionId = `block-navigation-appender-row__description_${ instanceId }`;
 
@@ -32,6 +51,7 @@ export default function BlockNavigationAppender( {
 
 	return (
 		<BlockNavigationLeaf
+			className={ classnames( { 'is-dragging': isDragging } ) }
 			level={ level }
 			position={ position }
 			rowCount={ rowCount }

packages/block-editor/src/components/block-navigation/block-contents.js

@@ -1,6 +1,12 @@
+/**
+ * External dependencies
+ */
+import classnames from 'classnames';
+
 /**
  * WordPress dependencies
  */
+import { useSelect } from '@wordpress/data';
 import { forwardRef } from '@wordpress/element';
 
 /**
@@ -9,6 +15,7 @@ import { forwardRef } from '@wordpress/element';
 import { useBlockNavigationContext } from './context';
 import BlockNavigationBlockSlot from './block-slot';
 import BlockNavigationBlockSelectButton from './block-select-button';
+import BlockDraggable from '../block-draggable';
 
 const BlockNavigationBlockContents = forwardRef(
 	(
@@ -24,33 +31,85 @@ const BlockNavigationBlockContents = forwardRef(
 		ref
 	) => {
 		const {
-			__experimentalFeatures: withBlockNavigationSlots,
+			__experimentalFeatures,
+			blockDropTarget = {},
 		} = useBlockNavigationContext();
 
-		return withBlockNavigationSlots ? (
-			<BlockNavigationBlockSlot
-				ref={ ref }
-				className="block-editor-block-navigation-block-contents"
-				block={ block }
-				onClick={ onClick }
-				isSelected={ isSelected }
-				position={ position }
-				siblingBlockCount={ siblingBlockCount }
-				level={ level }
-				{ ...props }
-			/>
-		) : (
-			<BlockNavigationBlockSelectButton
-				ref={ ref }
-				className="block-editor-block-navigation-block-contents"
-				block={ block }
-				onClick={ onClick }
-				isSelected={ isSelected }
-				position={ position }
-				siblingBlockCount={ siblingBlockCount }
-				level={ level }
-				{ ...props }
-			/>
+		const { clientId } = block;
+
+		const rootClientId = useSelect(
+			( select ) =>
+				select( 'core/block-editor' ).getBlockRootClientId(
+					clientId
+				) || '',
+			[ clientId ]
+		);
+
+		const {
+			rootClientId: dropTargetRootClientId,
+			clientId: dropTargetClientId,
+			dropPosition,
+		} = blockDropTarget;
+
+		const isDroppingBefore =
+			dropTargetRootClientId === rootClientId &&
+			dropTargetClientId === clientId &&
+			dropPosition === 'top';
+		const isDroppingAfter =
+			dropTargetRootClientId === rootClientId &&
+			dropTargetClientId === clientId &&
+			dropPosition === 'bottom';
+		const isDroppingToInnerBlocks =
+			dropTargetRootClientId === clientId && dropPosition === 'inside';
+
+		const className = classnames(
+			'block-editor-block-navigation-block-contents',
+			{
+				'is-dropping-before': isDroppingBefore,
+				'is-dropping-after': isDroppingAfter,
+				'is-dropping-to-inner-blocks': isDroppingToInnerBlocks,
+			}
+		);
+
+		return (
+			<BlockDraggable
+				clientIds={ [ block.clientId ] }
+				elementId={ `block-navigation-block-${ block.clientId }` }
+			>
+				{ ( { isDraggable, onDraggableStart, onDraggableEnd } ) =>
+					__experimentalFeatures ? (
+						<BlockNavigationBlockSlot
+							ref={ ref }
+							className={ className }
+							block={ block }
+							onClick={ onClick }
+							isSelected={ isSelected }
+							position={ position }
+							siblingBlockCount={ siblingBlockCount }
+							level={ level }
+							draggable={ isDraggable && __experimentalFeatures }
+							onDragStart={ onDraggableStart }
+							onDragEnd={ onDraggableEnd }
+							{ ...props }
+						/>
+					) : (
+						<BlockNavigationBlockSelectButton
+							ref={ ref }
+							className={ className }
+							block={ block }
+							onClick={ onClick }
+							isSelected={ isSelected }
+							position={ position }
+							siblingBlockCount={ siblingBlockCount }
+							level={ level }
+							draggable={ isDraggable && __experimentalFeatures }
+							onDragStart={ onDraggableStart }
+							onDragEnd={ onDraggableEnd }
+							{ ...props }
+						/>
+					)
+				}
+			</BlockDraggable>
 		);
 	}
 );

packages/block-editor/src/components/block-navigation/block-select-button.js

@@ -32,6 +32,9 @@ function BlockNavigationBlockSelectButton(
 		level,
 		tabIndex,
 		onFocus,
+		onDragStart,
+		onDragEnd,
+		draggable,
 	},
 	ref
 ) {
@@ -59,6 +62,9 @@ function BlockNavigationBlockSelectButton(
 				ref={ ref }
 				tabIndex={ tabIndex }
 				onFocus={ onFocus }
+				onDragStart={ onDragStart }
+				onDragEnd={ onDragEnd }
+				draggable={ draggable }
 			>
 				<BlockIcon icon={ blockType.icon } showColors />
 				{ blockDisplayName }

packages/block-editor/src/components/block-navigation/block.js

@@ -15,7 +15,7 @@ import {
 import { __ } from '@wordpress/i18n';
 import { moreVertical } from '@wordpress/icons';
 import { useState, useRef, useEffect } from '@wordpress/element';
-import { useDispatch } from '@wordpress/data';
+import { useDispatch, useSelect } from '@wordpress/data';
 
 /**
  * Internal dependencies
@@ -45,10 +45,24 @@ export default function BlockNavigationBlock( {
 	const cellRef = useRef( null );
 	const [ isHovered, setIsHovered ] = useState( false );
 	const [ isFocused, setIsFocused ] = useState( false );
+	const { clientId } = block;
+	const isDragging = useSelect(
+		( select ) => {
+			const { isBlockBeingDragged, isAncestorBeingDragged } = select(
+				'core/block-editor'
+			);
+
+			return (
+				isBlockBeingDragged( clientId ) ||
+				isAncestorBeingDragged( clientId )
+			);
+		},
+		[ clientId ]
+	);
+
 	const { selectBlock: selectEditorBlock } = useDispatch(
 		'core/block-editor'
 	);
-	const { clientId } = block;
 
 	const hasSiblings = siblingBlockCount > 0;
 	const hasRenderedMovers = showBlockMovers && hasSiblings;
@@ -74,6 +88,7 @@ export default function BlockNavigationBlock( {
 		<BlockNavigationLeaf
 			className={ classnames( {
 				'is-selected': isSelected,
+				'is-dragging': isDragging,
 			} ) }
 			onMouseEnter={ () => setIsHovered( true ) }
 			onMouseLeave={ () => setIsHovered( false ) }
@@ -83,6 +98,8 @@ export default function BlockNavigationBlock( {
 			position={ position }
 			rowCount={ rowCount }
 			path={ path }
+			id={ `block-navigation-block-${ clientId }` }
+			data-block={ clientId }
 		>
 			<TreeGridCell
 				className="block-editor-block-navigation-block__contents-cell"

packages/block-editor/src/components/block-navigation/style.scss

@@ -28,17 +28,55 @@ $tree-item-height: 36px;
 	// Use position relative for row animation.
 	position: relative;
 
+	&.is-dragging {
+		display: none;
+	}
+
 	.block-editor-block-navigation-block-contents {
 		display: flex;
 		align-items: center;
-		width: calc(100% - 0.8em);
+		width: 100%;
 		height: auto;
-		padding: $grid-unit-15 6px;
+		padding: $grid-unit-20 6px;
 		margin-top: auto;
 		margin-bottom: auto;
 		text-align: left;
 		color: $dark-gray-600;
 		border-radius: 2px;
+		position: relative;
+
+		&.is-dropping-before::before {
+			content: "";
+			position: absolute;
+			pointer-events: none;
+			transition: border-color 0.1s linear, border-style 0.1s linear, box-shadow 0.1s linear;
+			top: -2px;
+			right: 0;
+			left: 0;
+			border-top: 4px solid var(--wp-admin-theme-color);
+		}
+
+		&.is-dropping-after::before {
+			content: "";
+			position: absolute;
+			pointer-events: none;
+			transition: border-color 0.1s linear, border-style 0.1s linear, box-shadow 0.1s linear;
+			bottom: -2px;
+			right: 0;
+			left: 0;
+			border-bottom: 4px solid var(--wp-admin-theme-color);
+		}
+
+		&.is-dropping-to-inner-blocks::before {
+			content: "";
+			position: absolute;
+			pointer-events: none;
+			transition: border-color 0.1s linear, border-style 0.1s linear, box-shadow 0.1s linear;
+			bottom: -2px;
+			right: 0;
+			left: $icon-size;
+			border-bottom: 4px solid var(--wp-admin-theme-color);
+		}
 
 		.components-modal__content & {
 			padding-left: 0;

packages/block-editor/src/components/block-navigation/tree.js

@@ -3,14 +3,15 @@
  */
 
 import { __experimentalTreeGrid as TreeGrid } from '@wordpress/components';
-import { useMemo } from '@wordpress/element';
+import { useMemo, useRef } from '@wordpress/element';
 import { __ } from '@wordpress/i18n';
 
 /**
  * Internal dependencies
  */
 import BlockNavigationBranch from './branch';
 import { BlockNavigationContext } from './context';
+import useBlockNavigationDropZone from './use-block-navigation-drop-zone';
 
 /**
  * Wrap `BlockNavigationRows` with `TreeGrid`. BlockNavigationRows is a
@@ -24,17 +25,26 @@ export default function BlockNavigationTree( {
 	__experimentalFeatures,
 	...props
 } ) {
+	const treeGridRef = useRef();
+	let blockDropTarget = useBlockNavigationDropZone( treeGridRef );
+
+	if ( ! __experimentalFeatures ) {
+		blockDropTarget = undefined;
+	}
+
 	const contextValue = useMemo(
 		() => ( {
 			__experimentalFeatures,
+			blockDropTarget,
 		} ),
-		[ __experimentalFeatures ]
+		[ __experimentalFeatures, blockDropTarget ]
 	);
 
 	return (
 		<TreeGrid
 			className="block-editor-block-navigation-tree"
 			aria-label={ __( 'Block navigation structure' ) }
+			ref={ treeGridRef }
 		>
 			<BlockNavigationContext.Provider value={ contextValue }>
 				<BlockNavigationBranch { ...props } />