收到新订阅时，如何在导航标头中更新计数

Question

我正在使用GraphQL订阅来获取新用户时获取更新，一切正常，我正在收到更新，但是我无法从导航标头中更新导航标头中的通知计数渲染方法。

class ContactsList extends Component {
static navigationOptions = ({ navigation }) => {
    return {
        headerRight: (
            <View style={{ flexDirection: 'row' }}>
                <View style={{ marginEnd: 5 }}>
                    <Icon.Button
                        name="bell"
                        backgroundColor="#3b5998"
                        onPress={() => alert('Bell Pressed!!')}>
                    **//i want update the count here when new contact is created** 
                    </Icon.Button>
                </View>
            </View>
        ),
    };
};
render() {
    return (
        <View>
            <Subscription
                subscription={NEW_NOTIFICATION_SUBSCRIPTION}
                variables={{ token: this.state.golbalDashboardToken }} >
                {({ data, loading }) => {
                    if (loading) {
                        // alert('Loading Subcription');
                        return <Text>Loading Subscription</Text>
                    }
                    if (data) {
                        **// when new contact is created i will receive the data her**

                    }
                }
                }  
            </Subscription>
        </View
      );
}
}

创建新用户时，我将收到子标签中的数据

Answer 1

尝试以下：

 if (data && data !== oldData) {
     **// when new contact is created i will receive the data her**
     this.props.navigation.setParams({ data }); // << this
 }

在导航中

<Icon.Button
          name="bell"
          backgroundColor="#3b5998"
          onPress={() => alert('Bell Pressed!!')}>
          **//i want update the count here when new contact is created**
          const newData = navigation.getParam('data'); // this
 </Icon.Button>