问题
I'm working with the Citybik.es API (http://api.citybik.es/) to show data on a Leaflet map.
At the moment, the code is showing every item in the map, but after analysing I would like to organize the data a little bit allowing the user to drill down the information, when clicking on a marker. Something like this:
- Display number of networks per country (each marker represents a network, so to speak, each marker per country)
- Display number of stations per network
The response looks something like this:
Here's the JavaScript:
import React, { Component } from 'react';
import L from 'leaflet';
import { Map, TileLayer, Marker, Popup } from 'react-leaflet';
// code for map marker icon
var myIcon = L.icon({
iconUrl: 'data:image/png;base64,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',
iconSize: [25, 41],
iconAnchor: [12.5, 41],
popupAnchor: [0, -41]
});
class App extends Component {
state = {
location: {
lat: 51.505,
lng: -0.09,
},
bikeData: [],
haveUsersLocation: false,
zoom: 3,
}
//lifecycle method to get the bike information
componentDidMount() {
fetch('https://api.citybik.es/v2/networks')
.catch(error => {
console.log(error)
})
.then(res => res.json())
.then(response => {
const networkData = response.networks;
this.setState({
bikeData: networkData
});
})
}
render() {
const position = [this.state.location.lat, this.state.location.lng]
const bikeData = this.state.bikeData;
return (
<Map className="map" center={position} zoom={this.state.zoom}>
<TileLayer
attribution="&copy <a href="http://osm.org/copyright">OpenStreetMap</a> contributors"
url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
/>
{
bikeData && bikeData.map((data) => {
console.log(data)
return (
<Marker
icon={myIcon}
key={data.id}
position={[data.location.latitude, data.location.longitude]}>
<Popup>
Name: {data.name} <br />
Station Details: {[data.location.city, data.location.country]}
</Popup>
</Marker>
)
})
}
</Map>
)
}
}
ReactDOM.render(<App/>,
document.getElementById('root')
);
Thank you!
回答1:
Maybe something like this to get the count
const networkCountByCountry = new Map();
response.networks.forEach(network => {
const country = network.location.country
const countryObject = networkCountByCountry.has(country) ? networkCountByCountry.get(country) : {
id: country,
count: 0
};
countryObject.count = countryObject.count + 1
networkCountByCountry.set(countryObject.id, countryObject)
})
const networkCountByCountryArray = [...networkCountByCountry.values()]
Then, you can use a click event to filter to the selected country list.
A more complete example:
import L from "leaflet";
import { Map as MapLeaf, TileLayer, Marker, Popup } from "react-leaflet";
// code for map marker icon
var myIcon = L.icon({
iconUrl:
"data:image/png;base64,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",
iconSize: [25, 41],
iconAnchor: [12.5, 41],
popupAnchor: [0, -41]
});
class MapDisplay extends Component {
state = {
location: {
lat: 51.505,
lng: -0.09
},
selectedCountry: null,
bikeData: [],
haveUsersLocation: false,
zoom: 3
};
//lifecycle method to get the bike information
componentDidMount() {
fetch("https://api.citybik.es/v2/networks")
.catch(error => {
console.log(error);
})
.then(res => res.json())
.then(response => {
const networkData = response.networks;
const networkCountByCountry = new Map();
response.networks.forEach(network => {
const country = network.location.country;
const countryObject = networkCountByCountry.has(country)
? networkCountByCountry.get(country)
: { id: country, count: 0, location: network.location };
countryObject.count = countryObject.count + 1;
networkCountByCountry.set(countryObject.id, countryObject);
});
const networkCountByCountryArray = [...networkCountByCountry.values()];
this.setState({
bikeData: networkData,
bikeCountryData: networkCountByCountryArray
});
});
}
countryMarkerClick(country) {
console.log(country);
this.setState({ selectedCountry: country });
}
render() {
const position = [this.state.location.lat, this.state.location.lng];
if (this.state.selectedCountry) {
const bikeData = this.state.bikeData.filter(
network => network.location.country === this.state.selectedCountry
);
return (
<MapLeaf className="map" center={position} zoom={this.state.zoom}>
<TileLayer
attribution="&copy <a href="http://osm.org/copyright">OpenStreetMap</a> contributors"
url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
/>
{bikeData &&
bikeData.map(data => {
console.log(data);
return (
<Marker
icon={myIcon}
key={data.id}
position={[data.location.latitude, data.location.longitude]}
>
<Popup>
Name: {data.name} <br />
Station Details:{" "}
{[data.location.city, data.location.country]}
</Popup>
</Marker>
);
})}
</MapLeaf>
);
}
const bikeCountryData = this.state.bikeCountryData;
return (
<MapLeaf className="map" center={position} zoom={this.state.zoom}>
<TileLayer
attribution="&copy <a href="http://osm.org/copyright">OpenStreetMap</a> contributors"
url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
/>
{bikeCountryData &&
bikeCountryData.map(data => {
return (
<Marker
icon={myIcon}
key={data.id}
position={[data.location.latitude, data.location.longitude]}
>
<Popup>
Name: {data.id} <br />
Stations: {[data.count]} <br />
<span onClick={this.countryMarkerClick.bind(this, data.id)}>
{" "}
-->{" "}
</span>
</Popup>
</Marker>
);
})}
</MapLeaf>
);
}
}
来源：https://stackoverflow.com/questions/52557802/how-to-get-the-number-of-map-markers-per-country-reactjs