从第二个屏幕返回到第一个屏幕时更改Flatlist滚动索引

import React, { Component } from 'react';
import { FlatList } from 'react-native';

class FirstScreen extends Component {
  constructor(props) {
    super(props);
    this.state = {
      scrollIndex: 0, // 当前的滚动索引
    };
  }

  // 其他代码...
}

<FlatList
  data={yourData} // Flatlist的数据源
  renderItem={yourRenderItem} // 渲染每一项的方法
  onViewableItemsChanged={({ viewableItems }) => {
    if (viewableItems.length > 0) {
      const index = viewableItems[0].index;
      this.setState({ scrollIndex: index });
    }
  }}
/>

class SecondScreen extends Component {
  // 其他代码...

  goBackToFirstScreen = () => {
    const { navigation } = this.props;
    const { scrollIndex } = this.state;
    navigation.goBack(); // 返回到第一个屏幕
    navigation.state.params.updateScrollIndex(scrollIndex); // 传递滚动索引给第一个屏幕
  }

  // 其他代码...
}

class App extends Component {
  render() {
    return (
      <NavigationContainer>
        <Stack.Navigator>
          <Stack.Screen
            name="First"
            component={FirstScreen}
            options={({ navigation }) => ({
              headerLeft: () => (
                <Button
                  onPress={() => navigation.navigate('Second', {
                    updateScrollIndex: (index) => this.updateScrollIndex(index),
                  })}
                  title="Go to Second"
                />
              ),
            })}
          />
          <Stack.Screen name="Second" component={SecondScreen} />
        </Stack.Navigator>
      </NavigationContainer>
    );
  }

  updateScrollIndex = (index) => {
    this.setState({ scrollIndex: index });
  }
}