StackNavigator 的子组件在其父组件外部调用时呈现两次

Question

我使用 React Navigation 在我的 React Native 应用程序的屏幕之间导航。我的屏幕结构是：

 - DrawerNavigator    
    - HomeScreen    
    - MoviesStackNavigator    
      - MoviesListScreen    
      - MovieDetailsScreen    
    - DiscoverScreen

现在我想导航并将一些参数从 DiscoverScreen 传递到 MoviesListScreen。

这是我的代码：

DiscoverScreen.js

onSearchConfirm() {
    this.setState({searching: true})


    var params = {
        sort_by: this.state.sortBy,
        year: this.state.releaseYear,
        with_genres: this.state.genreIds.join(',')
    };

    const _this = this;

    return fetch(Configuration.TMDB_BASE_URL
                .concat('/discover/movie?')
                .concat(Utility.stringFromQueryParams({...params, api_key: Configuration.TMDB_API_KEY})))
        .then(response => response.json())
        .then(jsonResponse => {
            _this.setState({searching: false});

            const navigateAction = NavigationActions.navigate({
                routeName: 'MoviesList',
                params: {data: jsonResponse}
            })

            _this.props.navigation.dispatch(navigateAction)

        })
        .catch(err => console.error(err.toString()))
}

抽屉导航器：

export default MenuNavScreen = DrawerNavigator(
{
    Home: {
        screen: HomeScreen
    },
    Movies: {
        screen: MoviesStackNavigator
    },
    DiscoverMovies: {
        screen: DiscoverScreen
    },
    About: {
        screen: AboutScreen
    },
},
{
    initialRouteName: 'Home'
})

电影堆栈导航器：

export default MoviesStackNavigator = StackNavigator({
    MoviesList: {
        screen: MoviesListScreen
    },
    MovieDetails: {
        screen: MovieDetailsScreen
    },
});

最后，我检查参数的代码电影列表屏幕：

//...
componentWillMount() { //THIS IS CALLED TWICE

    if(!this.props.navigation.state.params) {
        MoviesService.getPopularMovies()
            .then(movies => {
                this.setState({movies: movies.results})
            })
            .catch(err => Alert.alert(err.toString()))
    }
    else {
        this.setState({movies: this.props.navigation.state.params.data.results})
    }
}
//...

嗯，最后一段代码执行了两次。第一次使用 "data" 参数未定义，第二次使用正确填充的参数。我的错误在哪里？谢谢大家:)

编辑：明确地说，这是上述问题的结果：

IMAGE

Answer 1

一段时间后，我意识到我可以通过用新的 DiscoverStackNavigator 替换 DiscoverScreen 然后将 DiscoverScreen、MoviesListScreen 和 MovieDetailsScreen 设置为其子屏幕来解决问题。所以我的代码现在看起来像这样：

抽屉导航器：

export default MenuNavScreen = DrawerNavigator(
{
    Home: {
        screen: HomeScreen
    },
    Movies: {
        screen: MoviesStackNavigator
    },
    DiscoverMovies: {
        screen: DiscoverStackNavigator
    },
    About: {
        screen: AboutScreen
    },
},
{
    initialRouteName: 'Home'
})

DiscoverStackNavigator:

export default DiscoverStackNavigator = StackNavigator({
    DiscoverMovies: {
        screen: DiscoverScreen
    }
    DiscoverMoviesList: {
        screen: MoviesListScreen
    },
    DiscoverMovieDetails: {
        screen: MovieDetailsScreen
    },
});

导航到 MoviesScreen：

onSearchConfirm() {
    //...code before

    return fetch(Configuration.TMDB_BASE_URL
                .concat('/discover/movie?')
                .concat(Utility.stringFromQueryParams({...params, api_key: Configuration.TMDB_API_KEY})))
        .then(response => response.json())
        .then(jsonResponse => {
            _this.setState({searching: false});

            const navigateAction = NavigationActions.navigate({
                routeName: 'DiscoverMoviesList', // we changed the route name
                params: {data: jsonResponse}
            })

            _this.props.navigation.dispatch(navigateAction)

        })
        .catch(err => console.error(err.toString()))
}

我不知道这是否是正确的方法，但效果很好。

StackNavigator 的子组件在其父组件外部调用时呈现两次

StackNavigator's child component rendered twice when called outside of its parent

reactjs

react-native

react-navigation