0Pull-to-refresh triggers data reloads when the user pulls down on a list. This can cause network requests and UI updates. If the data fetch or rendering is slow, it may drop below 60 frames per second, causing janky scrolling. Memory use spikes if large data sets are loaded without pagination or caching. Battery usage increases with frequent refreshes due to network and CPU activity.
RefreshControl component efficiently with minimal re-renders.FlatList or SectionList using keyExtractor and getItemLayout.Pull-to-refresh uses built-in React Native components like RefreshControl, so it adds negligible size to the app bundle. Startup time is unaffected since pull-to-refresh logic loads only when the user interacts with the list. However, if you add heavy third-party libraries for data fetching or UI, bundle size may increase.
UIRefreshControl under the hood, providing smooth and consistent pull-to-refresh behavior.Likely causes include fetching too much data on pull-to-refresh without pagination, causing slow network response and UI blocking. Another cause is inefficient list rendering causing frame drops. Also, multiple refresh triggers firing rapidly can overload the app. Check if data caching is missing or if heavy computations run on the main thread during refresh.
RefreshControl in a React Native app?RefreshControl is a component used inside scrollable views to provide pull-to-refresh behavior.RefreshControl inside a ScrollView?refreshControl prop expects a RefreshControl component with props refreshing and onRefresh.refreshing and onRefresh inside <RefreshControl /> as a JSX element.const [refreshing, setRefreshing] = React.useState(false);
const onRefresh = React.useCallback(() => {
setRefreshing(true);
setTimeout(() => setRefreshing(false), 2000);
}, []);
return (
<ScrollView refreshControl={
<RefreshControl refreshing={refreshing} onRefresh={onRefresh} />
}>
<Text>Pull down to refresh</Text>
</ScrollView>
);onRefresh sets refreshing to true, showing the spinner.setRefreshing(false) hides the spinner automatically.const [refreshing, setRefreshing] = React.useState(false);
function onRefresh() {
setRefreshing(true);
fetchData();
setRefreshing(false);
}
return (
<FlatList
data={data}
refreshControl={<RefreshControl refreshing={refreshing} onRefresh={onRefresh} />}
renderItem={({item}) => <Text>{item}</Text>}
/>
);setRefreshing(false) immediately after fetchData(), without waiting for data to load.SectionList that fetches new data asynchronously. Which approach correctly ensures the spinner shows during fetch and hides after completion?
const [refreshing, setRefreshing] = React.useState(false);
const onRefresh = async () => {
// What goes here?
};setRefreshing(true) to show spinner before starting data fetch.await fetchData() to wait for data, then call setRefreshing(false) to hide spinner after completion.Pass the test and this pattern moves unknown strong while earning +1 Grip toward your certificate.