Back button behavior is correct for the platform

Broken back-button behavior is the most reliably reported UX defect in mobile app reviews. On Android, a hardware back press that skips a screen, crashes the app, or silently does nothing fails WCAG 2.2 SC 2.1.1 (Keyboard), which requires keyboard-equivalent navigation for all functionality. Beyond accessibility compliance, unexpected back behavior corrupts navigation state in ways that can strand users mid-flow — stranded on a checkout confirmation with no path to their cart, or dropped to an empty stack with no way to recover.

React Navigation handles the default back behavior automatically for most stack setups — only intervene when you need to intercept it (e.g., unsaved-form confirmation). Use useFocusEffect with BackHandler to manage the Android hardware back button on screens that need custom logic:

import { useFocusEffect } from '@react-navigation/native'
import { BackHandler, Alert } from 'react-native'

function EditFormScreen({ navigation }) {
  const [isDirty, setIsDirty] = React.useState(false)

  useFocusEffect(
    React.useCallback(() => {
      const onBackPress = () => {
        if (isDirty) {
          Alert.alert('Discard changes?', '', [
            { text: 'Cancel', onPress: () => null },
            { text: 'Discard', onPress: () => navigation.goBack() },
          ])
          return true // prevent default
        }
        return false // use default
      }

      BackHandler.addEventListener('hardwareBackPress', onBackPress)
      return () => BackHandler.removeEventListener('hardwareBackPress', onBackPress)
    }, [isDirty, navigation])
  )
}

For screens without custom needs, do not add a BackHandler at all — letting React Navigation's default behavior run is correct.

• ID: back-button-behavior

• Severity: high

• What to look for: On Android, check for useFocusEffect or useEffect handling the hardware back button via BackHandler from react-native. On iOS, check for proper gesture handling of back swipe. Examine whether back button correctly pops from the current stack and handles nested navigators.

• Pass criteria: Count all BackHandler event listeners and back navigation handlers in the codebase. Android back button navigates up exactly 1 level in the stack or exits the app when at the root. iOS back gesture works correctly. No more than 0 unintended screens are popped per back action.

• Fail criteria: Back button crashes the app, navigates to an unexpected screen, or is unresponsive. Nested stack back behavior is broken.

• Skip (N/A) when: Never — back button behavior applies to all mobile apps.

• Detail on fail: Describe the issue. Example: "Pressing back on Android pops multiple screens instead of one" or "Back button on iOS is unresponsive in nested stacks"

• Remediation: Handle back button behavior with React Navigation's built-in support and BackHandler on Android:

  import { useFocusEffect } from '@react-navigation/native'
  import { BackHandler } from 'react-native'
  
  function ProductDetailScreen() {
    useFocusEffect(
      React.useCallback(() => {
        const onBackPress = () => {
          // Return true to prevent default back behavior, false to use default
          // Default behavior (return false) pops the current screen
          return false
        }
  
        BackHandler.addEventListener('hardwareBackPress', onBackPress)
  
        return () => BackHandler.removeEventListener('hardwareBackPress', onBackPress)
      }, [])
    )
  
    return <View>{/* screen content */}</View>
  }
  

  React Navigation handles most back behavior automatically — only customize if you need special handling (e.g., confirmation dialogs).