概述

#

我们改变了模态路由中 Overlay 条目的语义遍历顺序。现在,无障碍读屏软件(如 TalkBack 或 VoiceOver)会先聚焦模态路由的作用域,而不是其模态障碍物。

背景

#

模态路由有两个 Overlay 条目:作用域(scope)和模态障碍物(modal barrier)。作用域是模态路由的实际内容,而模态障碍物是路由的背景,如果其作用域未覆盖整个屏幕。如果模态路由的 barrierDismissible 返回 true,模态障碍物将变得可聚焦,因为用户可以通过点击模态障碍物来关闭模态路由。此更改特意将无障碍焦点设置为先聚焦作用域,然后再聚焦模态障碍物。

变更说明

#

我们在模态路由的两个 Overlay 条目上方添加了额外的语义节点。这些语义节点表示这两个 Overlay 条目的语义遍历顺序。这也改变了语义树的结构。

迁移指南

#

如果更新后,您的测试因语义树更改而失败,您可以预期在模态路由 Overlay 条目上方出现一个新节点来迁移您的代码。

迁移前的代码

dart
import 'dart:ui';

import 'package:flutter_test/flutter_test.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/material.dart';

void main() {
  testWidgets('example test', (WidgetTester tester) async {
    final SemanticsHandle handle =
        tester.binding.pipelineOwner.ensureSemantics();

    // Build our app and trigger a frame.
    await tester.pumpWidget(MaterialApp(home: Scaffold(body: Text('test'))));

    final SemanticsNode root =
        tester.binding.pipelineOwner.semanticsOwner.rootSemanticsNode;

    final SemanticsNode firstNode = getChild(root);
    expect(firstNode.rect, Rect.fromLTRB(0.0, 0.0, 800.0, 600.0));

    // Fixes the test by expecting an additional node above the scope route.
    final SemanticsNode secondNode = getChild(firstNode);
    expect(secondNode.rect, Rect.fromLTRB(0.0, 0.0, 800.0, 600.0));

    final SemanticsNode thirdNode = getChild(secondNode);
    expect(thirdNode.rect, Rect.fromLTRB(0.0, 0.0, 800.0, 600.0));
    expect(thirdNode.hasFlag(SemanticsFlag.scopesRoute), true);

    final SemanticsNode forthNode = getChild(thirdNode);
    expect(forthNode.rect, Rect.fromLTRB(0.0, 0.0, 56.0, 14.0));
    expect(forthNode.label, 'test');
    handle.dispose();
  });
}

SemanticsNode getChild(SemanticsNode node) {
  SemanticsNode child;
  bool visiter(SemanticsNode target) {
    child = target;
    return false;
  }

  node.visitChildren(visiter);
  return child;
}

迁移后的代码

dart
import 'dart:ui';

import 'package:flutter_test/flutter_test.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/material.dart';

void main() {
  testWidgets('example test', (WidgetTester tester) async {
    final SemanticsHandle handle =
        tester.binding.pipelineOwner.ensureSemantics();

    // Build our app and trigger a frame.
    await tester.pumpWidget(MaterialApp(home: Scaffold(body: Text('test'))));

    final SemanticsNode root =
        tester.binding.pipelineOwner.semanticsOwner.rootSemanticsNode;

    final SemanticsNode firstNode = getChild(root);
    expect(firstNode.rect, Rect.fromLTRB(0.0, 0.0, 800.0, 600.0));

    // Fixes the test by expecting an additional node above the scope route.
    final SemanticsNode secondNode = getChild(firstNode);
    expect(secondNode.rect, Rect.fromLTRB(0.0, 0.0, 800.0, 600.0));

    final SemanticsNode thirdNode = getChild(secondNode);
    expect(thirdNode.rect, Rect.fromLTRB(0.0, 0.0, 800.0, 600.0));
    expect(thirdNode.hasFlag(SemanticsFlag.scopesRoute), true);

    final SemanticsNode forthNode = getChild(thirdNode);
    expect(forthNode.rect, Rect.fromLTRB(0.0, 0.0, 56.0, 14.0));
    expect(forthNode.label, 'test');
    handle.dispose();
  });
}

SemanticsNode getChild(SemanticsNode node) {
  SemanticsNode child;
  bool visiter(SemanticsNode target) {
    child = target;
    return false;
  }

  node.visitChildren(visiter);
  return child;
}

时间线

#

已在版本中落地:1.19.0
稳定版本中:1.20

参考资料

#

API 文档

相关议题

相关 PR