Platform Differences

This library wraps platform-native file viewers, so behavior differs between iOS and Android.

Comparison

Behavior	iOS	Android
Preview style	In-app modal (QuickLook)	External app (Intent chooser)
Promise resolution	Resolves when user dismisses	Resolves immediately after launch
Multi-file preview	Swipeable gallery	Not supported
Editing/markup	Built-in markup tools	Not supported
Thumbnails	QLThumbnailGenerator	Not supported
Events	onDismiss, onEditedFile, onSavedEditedCopy	None
Remote files	Download to temp + preview	Download to cache + launch
Chooser title	Not applicable	Customizable via chooserTitle

iOS Details

On iOS, QLPreviewController is presented as a modal view controller. The user stays in your app and can dismiss the preview to return. This means:

• You know when the preview is dismissed (onDismiss event)
• You can react to edits (onEditedFile, onSavedEditedCopy)
• The promise resolves after dismissal, so you can chain actions:

await ExpoQuickLook.previewFile({ uri: path });
// User has dismissed the preview
console.log('Preview closed');

Android Details

On Android, an Intent is fired and the system picks an app to handle it. This means:

• Your app goes to the background
• You don't know when the user is done viewing
• The promise resolves right after launch
• No events are available

await ExpoQuickLook.previewFile({ uri: path });
// Intent was launched — user may still be viewing
console.log('Intent launched');

Custom Chooser Title

On Android, customize the "Open with" dialog title:

await ExpoQuickLook.previewFile({
  uri: path,
  chooserTitle: 'View document with',
});

Writing Cross-Platform Code

Use Platform.OS to handle differences:

import { Platform } from 'react-native';

await ExpoQuickLook.previewFile({ uri: path });

if (Platform.OS === 'ios') {
  // Preview was dismissed — safe to clean up
} else {
  // Intent launched — file may still be in use
}

Use canPreview to check if a file type is supported before attempting to open it:

const supported = await ExpoQuickLook.canPreview(path);
if (!supported) {
  // Show fallback UI
}