> For AI agents: the complete documentation index is available at /react-native-arrangement-view/v0.1/llms.txt, the full documentation bundle is available at /react-native-arrangement-view/v0.1/llms-full.txt.

# useHingeChange

Call the hook **inside a component rendered in either pane**. It observes the nearest [`ArrangementView`](/react-native-arrangement-view/v0.1/api/arrangement-view.md), keeping events associated with that view's scene. It is not a process-wide sensor subscription.

```tsx
import { Text } from 'react-native';
import { useHingeChange } from 'react-native-arrangement-view';

function Player() {
  const hinge = useHingeChange((next) => {
    // Use angle/status for effects or interactions.
    // Let ArrangementView handle adaptive layout.
    console.log(next.angle, next.status);
  });

  return (
    <Text>{hinge.angle === null ? 'No hinge' : `${hinge.angle} rad`}</Text>
  );
}
```

The callback is optional; the hook also returns the current `HingeState` and subscribes the component to updates. It invokes the callback with the initial unavailable state and then changed values. Changing the callback does not replay the current state.

## HingeState

```ts
type HingeState = {
  available: boolean;
  angle: number | null; // radians
  status: 'unknown' | 'closed' | 'partiallyOpen' | 'fullyOpen';
};
```

Before the first native update, without hardware, or when observation is disabled, the state is `{ available: false, angle: null, status: 'unknown' }`. Future unrecognized native statuses remain `unknown`. Apple's SwiftUI `onHingeChange` controls event timing and precision. The library does not infer status from angle thresholds, screen dimensions, or device names. Hook cleanup stops React subscriptions when their components unmount.