29 lines
920 B
Dart
29 lines
920 B
Dart
import 'package:flutter/material.dart';
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/// Utility to synchronously measure the size of a widget by building it offscreen in an Overlay.
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/// Only works for widgets with deterministic, constraint-based sizing (no async/layout dependencies).
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Size measureWidgetSize(BuildContext context, WidgetBuilder builder, {BoxConstraints? constraints}) {
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final key = GlobalKey();
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final overlay = Overlay.of(context);
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Size? measuredSize;
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final widget = Offstage(
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child: ConstrainedBox(
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constraints: constraints ?? const BoxConstraints(),
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child: Container(key: key, child: builder(context)),
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),
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);
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final entry = OverlayEntry(builder: (_) => widget);
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overlay.insert(entry);
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WidgetsBinding.instance.handleDrawFrame();
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final ctx = key.currentContext;
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if (ctx != null) {
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measuredSize = (ctx.findRenderObject() as RenderBox).size;
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}
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entry.remove();
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return measuredSize ?? Size.zero;
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}
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