How to create two columns with space beetwen in react native - flatList

Hi i'm new in React Native.

I am trying to create two columns layout with space beetween using react native component called flatList.

Here is my view Code:

<View style={styles.container}>
        <FlatList
            data={db}
            keyExtractor={ (item, index) => item.id }
            numColumns={2}
            renderItem={
                ({item}) => (
                    <TouchableWithoutFeedback  onPress ={() => showItemDetails(item.id)}>
                        <View style={styles.listItem}>
                            <Text style={styles.title}>{item.name}</Text>
                            <Image
                                style={styles.image}
                                source={{uri: item.image}}
                            />
                            <Text style={styles.price}>{item.price} zł</Text>
                        </View>
                    </TouchableWithoutFeedback>
                )
            }
        />
    </View>

Here is styles:

container: {
    flex: 1,
    flexDirection: 'row',
    justifyContent: 'space-between',
    padding: 10,
    marginBottom: 40
},
listItem: {
    maxWidth: Dimensions.get('window').width /2,
    flex:0.5,
    backgroundColor: '#fff',
    marginBottom: 10,
    borderRadius: 4,
},

And result is two columns but without space between. Could you help me resolve this problem ?