mobile-accessibility（移动辅助功能）

Mobile Accessibility Skill

This skill provides mobile accessibility reference data for React Native, Expo, iOS, and Android auditing. Used by mobile-accessibility.agent.md.

React Native Accessibility Props - Full Reference

Accessibility Role Values

Touch Target Size Requirements

Detection Pattern (React Native)

// Violation: TouchableOpacity below minimum
const styles = StyleSheet.create({
  closeBtn: { width: 24, height: 24 },          // FAIL - below 44pt
  iconBtn: { width: 32, height: 32 },            // FAIL - below 44pt
  navBtn: { padding: 4 },                        // CONDITIONAL - depends on content size
  compliant: { width: 44, height: 44 },          // PASS
  compliantWithPadding: { padding: 12 },         // PASS if content >= 20pt
});

iOS UIAccessibility - Quick Reference

SwiftUI Modifiers

SwiftUI Trait Values

isButton, isHeader, isLink, isImage, isStaticText, isSelected, isKeyboardKey, isSearchField, playsSound, isModal, updatesFrequently, startsMediaSession, allowsDirectInteraction, causesPageTurn, isTabBar, isSummaryElement

UIKit Properties

Android Jetpack Compose Semantics - Quick Reference

Role Values

Role.Button, Role.Checkbox, Role.DropdownList, Role.Image, Role.RadioButton, Role.Switch, Role.Tab

Common Violation Patterns and Fixes

RN-001: Missing accessibilityLabel on icon button

// VIOLATION
<TouchableOpacity onPress={close}>
  <Icon name="x" size={20} />
</TouchableOpacity>

// FIX
<TouchableOpacity
  onPress={close}
  accessibilityRole="button"
  accessibilityLabel="Close"
>
  <Icon name="x" size={20} aria-hidden />
</TouchableOpacity>

RN-002: Image missing label

// VIOLATION
<Image source={productImage} style={styles.product} />

// FIX - informational image
<Image
  source={productImage}
  style={styles.product}
  accessibilityLabel="Blue suede shoes, size 10"
/>

// FIX - decorative image
<Image
  source={decorativeBackground}
  style={styles.bg}
  accessible={false}
  importantForAccessibility="no"
/>

RN-003: TextInput missing label

// VIOLATION - placeholder is not a label
<TextInput placeholder="Email" value={email} onChangeText={setEmail} />

// FIX
<View>
  <Text nativeID="emailLabel">Email address</Text>
  <TextInput
    value={email}
    onChangeText={setEmail}
    accessibilityLabelledBy="emailLabel"
    accessibilityHint="Enter your email address"
    keyboardType="email-address"
    autoComplete="email"
  />
</View>

RN-004: Checkbox missing state

// VIOLATION
<TouchableOpacity onPress={toggle}>
  <Image source={checked ? checkedIcon : uncheckedIcon} />
  <Text>Accept terms</Text>
</TouchableOpacity>

// FIX
<TouchableOpacity
  onPress={toggle}
  accessibilityRole="checkbox"
  accessibilityState={{ checked }}
  accessibilityLabel="Accept terms and conditions"
>
  <Image source={checked ? checkedIcon : uncheckedIcon} accessible={false} />
  <Text>Accept terms</Text>
</TouchableOpacity>

RN-005: Modal not trapping focus

// VIOLATION - custom modal without VoiceOver trap
<View style={styles.modal}>
  <Text>Are you sure?</Text>
  <Button title="Confirm" onPress={confirm} />
</View>

// FIX - use Modal component (traps focus automatically) or set accessibilityViewIsModal
<Modal
  visible={visible}
  transparent
  accessibilityViewIsModal={true}  // traps VoiceOver
  onRequestClose={close}           // Android back button
>
  <View style={styles.overlay}>
    <Text>Are you sure?</Text>
    <Button title="Confirm" onPress={confirm} />
    <Button title="Cancel" onPress={close} />
  </View>
</Modal>

AND-001: Compose image missing content description

// VIOLATION
Image(
    painter = painterResource(id = R.drawable.product),
    contentDescription = null  // null = decorative, but wrong for informational image
)

// FIX - informational
Image(
    painter = painterResource(id = R.drawable.product),
    contentDescription = stringResource(R.string.product_image_description)
)

// FIX - truly decorative
Image(
    painter = painterResource(id = R.drawable.divider),
    contentDescription = null,
    modifier = Modifier.semantics { invisibleToUser() }
)

Testing Tool Commands

iOS Accessibility Inspector (Xcode)

Xcode -> Xcode menu -> Open Developer Tool -> Accessibility Inspector
- Run audit: Click "Audit" tab -> "Run Audit" button
- Inspect: "Inspection" tab -> hover over elements in Simulator
- Keyboard: Use +F7 to toggle VoiceOver in Simulator

Android Accessibility Scanner

# Install (Play Store or adb)
adb install com.google.android.apps.accessibility.auditor

# Enable TalkBack via ADB (for CI)
adb shell settings put secure enabled_accessibility_services \
  com.google.android.marvin.talkback/.TalkBackService

# Check accessibility node tree
adb shell uiautomator dump /sdcard/ui_dump.xml
adb pull /sdcard/ui_dump.xml

React Native Testing Library

npm install --save-dev @testing-library/react-native

import { render, screen, fireEvent } from '@testing-library/react-native';

test('button has accessible name and role', () => {
  render(<SubmitButton onPress={jest.fn()} />);
  const btn = screen.getByRole('button', { name: /submit/i });
  expect(btn).toBeTruthy();
});

test('checkbox updates state', () => {
  render(<TermsCheckbox />);
  const checkbox = screen.getByRole('checkbox', { name: /accept terms/i });
  expect(checkbox).toHaveAccessibilityState({ checked: false });
  fireEvent.press(checkbox);
  expect(checkbox).toHaveAccessibilityState({ checked: true });
});

Maestro (E2E)

# .maestro/accessibility-checks.yaml
appId: com.example.myapp
---
- launchApp
- assertVisible:
    label: "Submit form"
- tapOn:
    label: "Close"
- assertNotVisible:
    label: "Are you sure?"