opt dyn text

Signed-off-by: dom <githubaccount56556@proton.me>

lib/common/widgets/more_text/paragraph_more.dart

@@ -0,0 +1,149 @@
+import 'package:flutter/gestures.dart' show TapGestureRecognizer;
+import 'package:flutter/rendering.dart'
+    show
+        Size,
+        Color,
+        Offset,
+        TextSpan,
+        TextStyle,
+        InlineSpan,
+        TextScaler,
+        TextPainter,
+        VoidCallback,
+        HitTestEntry,
+        RenderParagraph,
+        PaintingContext,
+        BoxHitTestResult,
+        RenderComparison;
+
+class RenderParagraphMore extends RenderParagraph {
+  RenderParagraphMore(
+    super.text, {
+    super.textAlign,
+    required super.textDirection,
+    super.softWrap,
+    super.overflow,
+    // ignore: deprecated_member_use
+    super.textScaleFactor,
+    super.textScaler,
+    super.maxLines,
+    super.locale,
+    super.strutStyle,
+    super.textWidthBasis,
+    super.textHeightBehavior,
+    super.children,
+    super.selectionColor,
+    super.registrar,
+    required this._primary,
+    this._onShowMore,
+  });
+
+  Color _primary;
+
+  VoidCallback? _onShowMore;
+  set onShowMore(VoidCallback? onShowMore) {
+    if (_onShowMore != onShowMore) {
+      _onShowMore = onShowMore;
+      _tapGestureRecognizer?.onTap = onShowMore;
+    }
+  }
+
+  TapGestureRecognizer? _tapGestureRecognizer;
+
+  TextSpan _moreTextSpan([TextStyle? style]) => TextSpan(
+    style: (style ?? text.style!).copyWith(color: _primary),
+    text: '查看更多',
+    recognizer: _tapGestureRecognizer,
+  );
+  TextPainter? _morePainter;
+
+  bool didOverflowHeight = false;
+
+  @override
+  set textScaler(TextScaler value) {
+    if (textPainter.textScaler == value) {
+      return;
+    }
+    _morePainter
+      ?..textScaler = value
+      ..layout();
+    super.textScaler = value;
+  }
+
+  void setText(({InlineSpan text, Color primary}) params) {
+    final newText = params.text;
+    _primary = params.primary;
+    if (_morePainter != null) {
+      final textSpan = _moreTextSpan(newText.style);
+      switch (_morePainter!.text!.compareTo(textSpan)) {
+        case RenderComparison.paint:
+          _morePainter!.text = textSpan;
+        case RenderComparison.layout:
+          _morePainter!
+            ..text = textSpan
+            ..layout();
+        default:
+      }
+    }
+    super.text = newText;
+  }
+
+  @override
+  void performLayout() {
+    super.performLayout();
+
+    if (didOverflowHeight = textPainter.didExceedMaxLines) {
+      if (_onShowMore != null) {
+        _tapGestureRecognizer ??= TapGestureRecognizer()..onTap = _onShowMore;
+      }
+      _morePainter ??= TextPainter(
+        text: _moreTextSpan(),
+        textDirection: textDirection,
+        textScaler: textScaler,
+        locale: locale,
+      )..layout(maxWidth: constraints.maxWidth);
+      size = Size(
+        size.width,
+        constraints.constrainHeight(size.height + _morePainter!.height),
+      );
+    }
+  }
+
+  @override
+  void paint(PaintingContext context, Offset offset) {
+    super.paint(context, offset);
+
+    if (didOverflowHeight) {
+      _morePainter?.paint(
+        context.canvas,
+        offset + Offset(0, textPainter.height),
+      );
+    }
+  }
+
+  @override
+  bool hitTestChildren(BoxHitTestResult result, {required Offset position}) {
+    if (_tapGestureRecognizer != null) {
+      if (_morePainter != null) {
+        if (position.dx < _morePainter!.width) {
+          final height = textPainter.height;
+          if (position.dy > height &&
+              position.dy < height + _morePainter!.height) {
+            result.add(HitTestEntry(_morePainter!.text as TextSpan));
+            return true;
+          }
+        }
+      }
+    }
+    return super.hitTestChildren(result, position: position);
+  }
+
+  @override
+  void dispose() {
+    _tapGestureRecognizer?.dispose();
+    _tapGestureRecognizer = null;
+    _morePainter?.dispose();
+    _morePainter = null;
+    super.dispose();
+  }
+}