javascript - 动态更新父状态

Question

我正在尝试根据子组件的输入值更新父组件的状态并再次渲染组件。

我有 App、Map 和 ListPlaces 组件。 Map 组件显示地图和标记，并从 App 组件中获取标记作为道具。

ListPlaces 组件有自己的状态（searchQuery）和方法（updateQuery）。基本上它使用正则表达式并根据输入过滤结果并在列表元素中显示过滤后的值。没关系，但是，我需要的远不止这些。我想在这里做什么？根据输入值的变化，我想更新我的标记（App 组件中的状态）并再次重新渲染我的地图组件以仅在地图上显示相关标记。想法是基本的，但我无法实现它。

当我尝试更改实际上是数组的标记时，它将为 0。我将分享我的所有代码，但我需要说我认为问题可能与输入元素（ListPlaces）中的 onChange 方法有关

应用程序.js

class App extends Component {
    constructor(props) {
        super(props);
        this.state = {
            places: [],
            markers: [],
            markerID: -1,
            newmarkers: []
        };

        this.changeMarkers = this.changeMarkers.bind(this);
    }

    componentDidMount() {
        fetch(
            "api_url"
        )
            .then(response => response.json())
            .then(data => {
                this.setState({
                    places: data.response.venues,
                    markers: data.response.venues
                });
            })
            .catch(error => {
                console.log("Someting went wrong ", error);
            });
    }

    openInfo = (e, id) => {
        this.setState({
            markerID: id
        });
    };

    closeInfo = () => {
        this.setState({
            markerID: -1
        });
    };

    changeMarkers = newValue => {
        const newmarkers = this.state.places.filter(
            place => place.name === newValue
        );
        this.setState({
            markers: newmarkers
        });
    };

    toggleListPlaces = () => {
        const nav = document.getElementById("nav-toggle");
        const body = document.getElementsByTagName("body")[0];

        nav.classList.toggle("active");

        if (body.classList.contains("show-nav")) {
            body.classList.remove("show-nav");
        } else {
            // If sidebar is hidden:
            body.classList.add("show-nav");
        }
    };

    render() {
        return (
            <div className="App">
                <Map
                    role="application"
                    places={this.state.places}
                    markers={this.state.markers}
                    openInfoHandler={this.openInfo}
                    closeInfoHandler={this.closeInfo}
                    markerID={this.state.markerID}
                    googleMapURL="map_url"
                    loadingElement={<div style={{ height: "100%" }} />}
                    containerElement={<div style={{ height: "100%" }} />}
                    mapElement={<div style={{ height: "100%" }} />}
                />
                <ListPlaces
                    toggleListHandler={this.toggleListPlaces}
                    locations={this.state.places}
                    openInfoHandler={this.openInfo}
                    changeMarkersHandler={this.changeMarkers}
                />
            </div>
        );
    }
}

export default App;

列表地点

class ListPlaces extends Component {
    state = {
        searchQuery: ""
    };

    updateQuery = query => {
        this.setState({ searchQuery: query});
    };

    render() {
        const { toggleListHandler, locations, openInfoHandler, changeMarkersHandler} = this.props;
        let showLocations;
        if (this.state.searchQuery) {
            const match = new RegExp(escapeRegExp(this.state.searchQuery), "i");
            showLocations = locations.filter(location =>match.test(location.name));
        } else {
            showLocations = locations;
        }

        return (
            <div>
                <aside>
                    <h2>Restaurants</h2>
                    <nav>
                        <div className="search-area">
                            <input
                                className="search-input"
                                type="text"
                                placeholder="Search Restaurant"
                                value={this.state.searchQuery}
                                onChange={e => {this.updateQuery(e.target.value); changeMarkersHandler(e.target.value)}}
                            />
                        </div>
                        <ul>
                            {showLocations.map(location => {
                                return (
                                    <li
                                        key={location.id}
                                        onClick={e =>
                                            openInfoHandler(e, location.id)
                                        }
                                    >
                                        {location.name}
                                    </li>
                                );
                            })}
                        </ul>
                    </nav>
                    <p>Information provided by Foursquare</p>
                </aside>
                <a
                    onClick={toggleListHandler}
                    id="nav-toggle"
                    className="position"
                >
                    <span />
                </a>

            </div>
        );
    }
}

export default ListPlaces;

地图

const Map = withScriptjs(withGoogleMap((props) =>

    <GoogleMap
        defaultZoom={14}
        defaultCenter={{ lat: 48.2854790, lng: -143.1407394 }}
        >
        {props.markers.map(restaurant => {
            let marker = (
                <Marker
                    id={restaurant.id}
                    key={restaurant.id}
                    name={restaurant.name}
                    position={{lat: restaurant.location.lat, lng: restaurant.location.lng}}
                    address={restaurant.location.address}
                    defaultAnimation={window.google.maps.Animation.DROP} // Should be 1 or 2 according to Stackoverflow
                    onClick={e => {props.openInfoHandler(e, restaurant.id)}}
                    animation = {props.markerID === restaurant.id && window.google.maps.Animation.BOUNCE}
                    >
                    {props.markerID === restaurant.id && (
                    <InfoWindow onCloseClick={e => {props.closeInfoHandler()}}>
                      <div className="info-window">
                        <p className="restaurant-name">{restaurant.name}</p>
                        <p className="restaurant-address">{restaurant.location.address}</p>
                      </div>
                      </InfoWindow>
                        )}

                    </Marker>
                );
            return marker;
        })}

        </GoogleMap>
    ))

export default Map;

标签： javascriptreactjs

Answer 1

您走在正确的轨道上-您需要将过滤器值/过滤器操作提升到公共父级

App.js

class App extends React.Component {
  onChangeFilter = (newFilter) => {
    this.setState({ filter: newFilter })
  }

  render () {
    const { filter, places } = this.state
    const mPlaces = places.filter(/* filter places here */)

    return (
      <div className="App">
        <ListPlaces 
          places={ mPlaces }
          onChangeFilter={ this.onChangeFilter }
          ...
        />

        <Map 
          locations={ mPlaces }
          ...
        />
      </div>
    )
  }
}

ListPlaces.js

class ListPlaces extends React.Component {
  updateQuery = (query) => {
    this.props.onChangeFilter(query)
  }

  ...
}

这是 React 中的常见模式 - 如此常见，它在 React 文档中有自己的页面。