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samples/simplistic_editor/lib/basic_text_field.dart

171 lines
5.8 KiB

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'basic_text_input_client.dart';
/// A basic text field. Defines the appearance of a basic text input client.
class BasicTextField extends StatefulWidget {
const BasicTextField({
super.key,
required this.controller,
required this.style,
required this.focusNode,
});
final TextEditingController controller;
final TextStyle style;
final FocusNode focusNode;
@override
State<BasicTextField> createState() => _BasicTextFieldState();
}
class _BasicTextFieldState extends State<BasicTextField> {
final GlobalKey<BasicTextInputClientState> textInputClientKey =
GlobalKey<BasicTextInputClientState>();
BasicTextInputClientState? get _textInputClient =>
textInputClientKey.currentState;
RenderEditable get _renderEditable => _textInputClient!.renderEditable;
// For text selection gestures.
// The viewport offset pixels of the [RenderEditable] at the last drag start.
double _dragStartViewportOffset = 0.0;
late DragStartDetails _startDetails;
// For text selection.
TextSelectionControls? _textSelectionControls;
bool _showSelectionHandles = false;
bool _shouldShowSelectionHandles(SelectionChangedCause? cause) {
// When the text field is activated by something that doesn't trigger the
// selection overlay, we shouldn't show the handles either.
if (cause == SelectionChangedCause.keyboard) {
return false;
}
if (cause == SelectionChangedCause.longPress ||
cause == SelectionChangedCause.scribble) {
return true;
}
if (widget.controller.text.isNotEmpty) {
return true;
}
return false;
}
void _handleSelectionChanged(
TextSelection selection, SelectionChangedCause? cause) {
final bool willShowSelectionHandles = _shouldShowSelectionHandles(cause);
if (willShowSelectionHandles != _showSelectionHandles) {
setState(() {
_showSelectionHandles = willShowSelectionHandles;
});
}
}
void _onDragUpdate(DragUpdateDetails details) {
final Offset startOffset = _renderEditable.maxLines == 1
? Offset(_renderEditable.offset.pixels - _dragStartViewportOffset, 0.0)
: Offset(0.0, _renderEditable.offset.pixels - _dragStartViewportOffset);
_renderEditable.selectPositionAt(
from: _startDetails.globalPosition - startOffset,
to: details.globalPosition,
cause: SelectionChangedCause.drag,
);
}
void _onDragStart(DragStartDetails details) {
_startDetails = details;
_dragStartViewportOffset = _renderEditable.offset.pixels;
}
@override
Widget build(BuildContext context) {
switch (Theme.of(this.context).platform) {
case TargetPlatform.iOS:
_textSelectionControls = cupertinoTextSelectionControls;
break;
case TargetPlatform.macOS:
_textSelectionControls = cupertinoDesktopTextSelectionControls;
break;
case TargetPlatform.android:
case TargetPlatform.fuchsia:
_textSelectionControls = materialTextSelectionControls;
break;
case TargetPlatform.linux:
_textSelectionControls = desktopTextSelectionControls;
break;
case TargetPlatform.windows:
_textSelectionControls = desktopTextSelectionControls;
break;
}
return FocusTrapArea(
focusNode: widget.focusNode,
child: GestureDetector(
behavior: HitTestBehavior.translucent,
onPanStart: (dragStartDetails) => _onDragStart(dragStartDetails),
onPanUpdate: (dragUpdateDetails) => _onDragUpdate(dragUpdateDetails),
onTap: () {
_textInputClient!.requestKeyboard();
},
onTapDown: (tapDownDetails) {
_renderEditable.handleTapDown(tapDownDetails);
_renderEditable.selectPosition(cause: SelectionChangedCause.tap);
},
onLongPressMoveUpdate: (longPressMoveUpdateDetails) {
switch (Theme.of(this.context).platform) {
case TargetPlatform.iOS:
case TargetPlatform.macOS:
_renderEditable.selectPositionAt(
from: longPressMoveUpdateDetails.globalPosition,
cause: SelectionChangedCause.longPress,
);
break;
case TargetPlatform.android:
case TargetPlatform.fuchsia:
case TargetPlatform.linux:
case TargetPlatform.windows:
_renderEditable.selectWordsInRange(
from: longPressMoveUpdateDetails.globalPosition -
longPressMoveUpdateDetails.offsetFromOrigin,
to: longPressMoveUpdateDetails.globalPosition,
cause: SelectionChangedCause.longPress,
);
break;
}
},
onLongPressEnd: (longPressEndDetails) =>
_textInputClient!.showToolbar(),
onHorizontalDragStart: (dragStartDetails) =>
_onDragStart(dragStartDetails),
onHorizontalDragUpdate: (dragUpdateDetails) =>
_onDragUpdate(dragUpdateDetails),
child: SizedBox(
height: double.infinity,
width: MediaQuery.of(context).size.width,
child: Container(
decoration: BoxDecoration(
border: Border.all(color: Colors.black),
borderRadius: const BorderRadius.all(Radius.circular(4.0)),
),
child: BasicTextInputClient(
key: textInputClientKey,
controller: widget.controller,
style: widget.style,
focusNode: widget.focusNode,
selectionControls: _textSelectionControls,
onSelectionChanged: _handleSelectionChanged,
showSelectionHandles: _showSelectionHandles,
),
),
),
),
);
}
}