new1

export default class recentChatListScreen extends Component
{
    constructor(props) {
        super(props);
        this.state = { elevation: 0 };
    }

    onScroll = (e) => {
        const { contentOffset } = e.nativeEvent;

        if (contentOffset.y > 0) {
            this.setState({ elevation: 48 });
        } else {
            this.setState({ elevation: 0 });
        }
    };

    .
    .
    .
    .
    .
    render() {
        return (
            <ThemeProvider uiTheme={uiTheme}>
                <View style={styles.contentWrapper}>
                    <View>
                        <Toolbar
                            .
                            .
                            .
                            style={{container: getPlatformElevation(this.state.elevation)}}
                        />
                    </View>
                    <View style={styles.chatListContainer}>
                        <FlatList
                            data={[..]}
                            renderItem={this._renderItem}
                            keyExtractor={item => item.userId}
                            onScroll={this.onScroll}
                        />