using System; using System.Collections.Generic; using Unity.UIWidgets.animation; using Unity.UIWidgets.foundation; using Unity.UIWidgets.gestures; using Unity.UIWidgets.rendering; using Unity.UIWidgets.scheduler; using Unity.UIWidgets.service; using Unity.UIWidgets.ui; namespace Unity.UIWidgets.widgets { public enum TextSelectionHandleType { left, right, collapsed, } enum _TextSelectionHandlePosition { start, end } public delegate void TextSelectionOverlayChanged(TextEditingValue value, Rect caretRect); public abstract class TextSelectionControls { public abstract Widget buildHandle(BuildContext context, TextSelectionHandleType type, float textLineHeight); public abstract Widget buildToolbar(BuildContext context, Rect globalEditableRegion, Offset position, TextSelectionDelegate selectionDelegate); public abstract Size handleSize { get; } public virtual bool canCut(TextSelectionDelegate selectionDelegate) { return !selectionDelegate.textEditingValue.selection.isCollapsed; } public virtual bool canCopy(TextSelectionDelegate selectionDelegate) { return !selectionDelegate.textEditingValue.selection.isCollapsed; } public virtual bool canPaste(TextSelectionDelegate selectionDelegate) { // TODO in flutter: return false when clipboard is empty return true; } public virtual bool canSelectAll(TextSelectionDelegate selectionDelegate) { return selectionDelegate.textEditingValue.text.isEmpty() && selectionDelegate.textEditingValue.selection.isCollapsed; } public void handleCut(TextSelectionDelegate selectionDelegate) { TextEditingValue value = selectionDelegate.textEditingValue; Clipboard.setData(new ClipboardData( text: value.selection.textInside(value.text) )); selectionDelegate.textEditingValue = new TextEditingValue( text: value.selection.textBefore(value.text) + value.selection.textAfter(value.text), selection: TextSelection.collapsed( offset: value.selection.start ) ); selectionDelegate.bringIntoView(selectionDelegate.textEditingValue.selection.extendPos); selectionDelegate.hideToolbar(); } public void handleCopy(TextSelectionDelegate selectionDelegate) { TextEditingValue value = selectionDelegate.textEditingValue; Clipboard.setData(new ClipboardData( text: value.selection.textInside(value.text) )); selectionDelegate.textEditingValue = new TextEditingValue( text: value.text, selection: TextSelection.collapsed(offset: value.selection.end) ); selectionDelegate.bringIntoView(selectionDelegate.textEditingValue.selection.extendPos); selectionDelegate.hideToolbar(); } public void handlePaste(TextSelectionDelegate selectionDelegate) { TextEditingValue value = selectionDelegate.textEditingValue; // Snapshot the input before using `await`. Clipboard.getData(Clipboard.kTextPlain).Then((data) => { if (data != null) { selectionDelegate.textEditingValue = new TextEditingValue( text: value.selection.textBefore(value.text) + data.text + value.selection.textAfter(value.text), selection: TextSelection.collapsed( offset: value.selection.start + data.text.Length ) ); } selectionDelegate.bringIntoView(selectionDelegate.textEditingValue.selection.extendPos); selectionDelegate.hideToolbar(); }); } public void handleSelectAll(TextSelectionDelegate selectionDelegate) { selectionDelegate.textEditingValue = new TextEditingValue( text: selectionDelegate.textEditingValue.text, selection: new TextSelection( baseOffset: 0, extentOffset: selectionDelegate.textEditingValue.text.Length ) ); selectionDelegate.bringIntoView(selectionDelegate.textEditingValue.selection.extendPos); } } public class TextSelectionOverlay { public TextSelectionOverlay(TextEditingValue value = null, BuildContext context = null, Widget debugRequiredFor = null, LayerLink layerLink = null, RenderEditable renderObject = null, TextSelectionControls selectionControls = null, TextSelectionDelegate selectionDelegate = null) { D.assert(value != null); D.assert(context != null); this.context = context; this.debugRequiredFor = debugRequiredFor; this.layerLink = layerLink; this.renderObject = renderObject; this.selectionControls = selectionControls; this.selectionDelegate = selectionDelegate; this._value = value; OverlayState overlay = Overlay.of(context); D.assert(overlay != null); this._handleController = new AnimationController(duration: _fadeDuration, vsync: overlay); this._toolbarController = new AnimationController(duration: _fadeDuration, vsync: overlay); } public readonly BuildContext context; public readonly Widget debugRequiredFor; public readonly LayerLink layerLink; public readonly RenderEditable renderObject; public readonly TextSelectionControls selectionControls; public readonly TextSelectionDelegate selectionDelegate; public static TimeSpan _fadeDuration = TimeSpan.FromMilliseconds(150); AnimationController _handleController; AnimationController _toolbarController; Animation _handleOpacity { get { return this._handleController.view; } } Animation _toolbarOpacity { get { return this._toolbarController.view; } } TextEditingValue _value; List _handles; OverlayEntry _toolbar; TextSelection _selection { get { return this._value.selection; } } public void showHandles() { D.assert(this._handles == null); this._handles = new List { new OverlayEntry(builder: (BuildContext context) => this._buildHandle(context, _TextSelectionHandlePosition.start)), new OverlayEntry(builder: (BuildContext context) => this._buildHandle(context, _TextSelectionHandlePosition.end)), }; Overlay.of(this.context, debugRequiredFor: this.debugRequiredFor).insertAll(this._handles); this._handleController.forward(from: 0.0f); } public void showToolbar() { D.assert(this._toolbar == null); this._toolbar = new OverlayEntry(builder: this._buildToolbar); Overlay.of(this.context, debugRequiredFor: this.debugRequiredFor).insert(this._toolbar); this._toolbarController.forward(from: 0.0f); } public void update(TextEditingValue newValue) { if (this._value == newValue) { return; } this._value = newValue; if (SchedulerBinding.instance.schedulerPhase == SchedulerPhase.persistentCallbacks) { SchedulerBinding.instance.addPostFrameCallback((duration) => this._markNeedsBuild()); } else { this._markNeedsBuild(); } } public void updateForScroll() { this._markNeedsBuild(); } void _markNeedsBuild() { if (this._handles != null) { this._handles[0].markNeedsBuild(); this._handles[1].markNeedsBuild(); } this._toolbar?.markNeedsBuild(); } public bool handlesAreVisible { get { return this._handles != null; } } public bool toolbarIsVisible { get { return this._toolbar != null; } } public void hide() { if (this._handles != null) { this._handles[0].remove(); this._handles[1].remove(); this._handles = null; } this._toolbar?.remove(); this._toolbar = null; this._handleController.stop(); this._toolbarController.stop(); } public void dispose() { this.hide(); this._handleController.dispose(); this._toolbarController.dispose(); } Widget _buildHandle(BuildContext context, _TextSelectionHandlePosition position) { if ((this._selection.isCollapsed && position == _TextSelectionHandlePosition.end) || this.selectionControls == null) { return new Container(); // hide the second handle when collapsed } return new FadeTransition( opacity: this._handleOpacity, child: new _TextSelectionHandleOverlay( onSelectionHandleChanged: (TextSelection newSelection) => { this._handleSelectionHandleChanged(newSelection, position); }, onSelectionHandleTapped: this._handleSelectionHandleTapped, layerLink: this.layerLink, renderObject: this.renderObject, selection: this._selection, selectionControls: this.selectionControls, position: position ) ); } Widget _buildToolbar(BuildContext context) { if (this.selectionControls == null) { return new Container(); } // Find the horizontal midpoint, just above the selected text. List endpoints = this.renderObject.getEndpointsForSelection(this._selection); Offset midpoint = new Offset( (endpoints.Count == 1) ? endpoints[0].point.dx : (endpoints[0].point.dx + endpoints[1].point.dx) / 2.0f, endpoints[0].point.dy - this.renderObject.preferredLineHeight ); Rect editingRegion = Rect.fromPoints(this.renderObject.localToGlobal(Offset.zero), this.renderObject.localToGlobal(this.renderObject.size.bottomRight(Offset.zero)) ); return new FadeTransition( opacity: this._toolbarOpacity, child: new CompositedTransformFollower( link: this.layerLink, showWhenUnlinked: false, offset: -editingRegion.topLeft, child: this.selectionControls.buildToolbar(context, editingRegion, midpoint, this.selectionDelegate) ) ); } void _handleSelectionHandleChanged(TextSelection newSelection, _TextSelectionHandlePosition position) { TextPosition textPosition = null; switch (position) { case _TextSelectionHandlePosition.start: textPosition = newSelection.basePos; break; case _TextSelectionHandlePosition.end: textPosition = newSelection.extendPos; break; } this.selectionDelegate.textEditingValue = this._value.copyWith(selection: newSelection, composing: TextRange.empty); this.selectionDelegate.bringIntoView(textPosition); } void _handleSelectionHandleTapped() { if (this._value.selection.isCollapsed) { if (this._toolbar != null) { this._toolbar?.remove(); this._toolbar = null; } else { this.showToolbar(); } } } } class _TextSelectionHandleOverlay : StatefulWidget { internal _TextSelectionHandleOverlay( Key key = null, TextSelection selection = null, _TextSelectionHandlePosition position = _TextSelectionHandlePosition.start, LayerLink layerLink = null, RenderEditable renderObject = null, ValueChanged onSelectionHandleChanged = null, VoidCallback onSelectionHandleTapped = null, TextSelectionControls selectionControls = null ) : base(key: key) { this.selection = selection; this.position = position; this.layerLink = layerLink; this.renderObject = renderObject; this.onSelectionHandleChanged = onSelectionHandleChanged; this.onSelectionHandleTapped = onSelectionHandleTapped; this.selectionControls = selectionControls; } public readonly TextSelection selection; public readonly _TextSelectionHandlePosition position; public readonly LayerLink layerLink; public readonly RenderEditable renderObject; public readonly ValueChanged onSelectionHandleChanged; public readonly VoidCallback onSelectionHandleTapped; public readonly TextSelectionControls selectionControls; public override State createState() { return new _TextSelectionHandleOverlayState(); } } class _TextSelectionHandleOverlayState : State<_TextSelectionHandleOverlay> { Offset _dragPosition; void _handleDragStart(DragStartDetails details) { this._dragPosition = details.globalPosition + new Offset(0.0f, -this.widget.selectionControls.handleSize.height); } void _handleDragUpdate(DragUpdateDetails details) { this._dragPosition += details.delta; TextPosition position = this.widget.renderObject.getPositionForPoint(this._dragPosition); if (this.widget.selection.isCollapsed) { this.widget.onSelectionHandleChanged(TextSelection.fromPosition(position)); return; } TextSelection newSelection = null; switch (this.widget.position) { case _TextSelectionHandlePosition.start: newSelection = new TextSelection( baseOffset: position.offset, extentOffset: this.widget.selection.extentOffset ); break; case _TextSelectionHandlePosition.end: newSelection = new TextSelection( baseOffset: this.widget.selection.baseOffset, extentOffset: position.offset ); break; } if (newSelection.baseOffset >= newSelection.extentOffset) { return; // don't allow order swapping. } this.widget.onSelectionHandleChanged(newSelection); } void _handleTap() { this.widget.onSelectionHandleTapped(); } public override Widget build(BuildContext context) { List endpoints = this.widget.renderObject.getEndpointsForSelection(this.widget.selection); Offset point = null; TextSelectionHandleType type = TextSelectionHandleType.left; switch (this.widget.position) { case _TextSelectionHandlePosition.start: point = endpoints[0].point; type = this._chooseType(endpoints[0], TextSelectionHandleType.left, TextSelectionHandleType.right); break; case _TextSelectionHandlePosition.end: D.assert(endpoints.Count == 2); point = endpoints[1].point; type = this._chooseType(endpoints[1], TextSelectionHandleType.right, TextSelectionHandleType.left); break; } return new CompositedTransformFollower( link: this.widget.layerLink, showWhenUnlinked: false, child: new GestureDetector( onPanStart: this._handleDragStart, onPanUpdate: this._handleDragUpdate, onTap: this._handleTap, child: new Stack( overflow: Overflow.visible, children: new List() { new Positioned( left: point.dx, top: point.dy, child: this.widget.selectionControls.buildHandle(context, type, this.widget.renderObject.preferredLineHeight) ) } ) ) ); } TextSelectionHandleType _chooseType( TextSelectionPoint endpoint, TextSelectionHandleType ltrType, TextSelectionHandleType rtlType ) { if (this.widget.selection.isCollapsed) { return TextSelectionHandleType.collapsed; } D.assert(endpoint.direction != null); switch (endpoint.direction) { case TextDirection.ltr: return ltrType; case TextDirection.rtl: return rtlType; } D.assert(() => throw new UIWidgetsError($"invalid endpoint.direction {endpoint.direction}")); return ltrType; } } }