我在将Leaflet和React一起使用时遇到了问题,问题在于Leaflet还希望控制DOM渲染。目前,国家将根据后端信息的特定颜色代码(1-100之间的范围)正确着色。但是它每分钟更新一次,在更新后,国家的颜色不会改变,但是如果你将鼠标悬停在特定的国家上,则颜色会改变。以下是我的源代码:
import React from 'react';
import L from 'leaflet';
import countries from './countries.js';
var Worldmap = React.createClass({
render: function() {
if(!this.props.data)
return <div> loading world map .. </div>;
let dataratio = this.props.data; // Props from main component
let size = Object.keys(dataratio).length; // Do we have data?
if(size > 1) { // If we do have data, ..
let dataratioToArr = Object.keys(dataratio).map(data => [ data, dataratio[data]]); // Conv. map to multidimensional array
let featuresArr = countries.features; // array of all countries in array features from countries.js
for(let i = 0; i < featuresArr.length; i++) // i = 178(no. of countries)
for(let j = 0; j < dataratioToArr.length; j++) // j = no. of countries we have with dataratio > 1 from backend
if(dataratioToArr[j][0] == featuresArr[i].id) // If ISO-3 compliant ID of country(f.e. "USA") matches, push a "data" property to countries.js
featuresArr[i].properties.data = dataratioToArr[j][1];
}
return(
<div id="leafletmap" style={{width: "100%", height: "80%", border: "2px solid black" }} />
)
},
componentDidMount : function() {
let geolocation = [];
// Retrieve geoloc coordinates
navigator.geolocation.getCurrentPosition(function(position) {
let lat = position.coords.latitude;
let lon = position.coords.longitude;
if(lat != null && lon != null) // If we can get latitude and longitude, reset geolocation and push values.
geolocation.length = 0;
geolocation.push(lat, lon);
if(!lat || !lon) // If we can't get latitude or longitude, set a default value.
geolocation = [0,0];
let map = L.map('leafletmap').setView(geolocation, 3); // ([coordinates], zoomlevel)
let info = L.control();
info.onAdd = function (map) {
this._div = L.DomUtil.create('div', 'info');
this.update();
return this._div;
};
info.update = function (props) {
this._div.innerHTML = '<h4>Data ratio</h4>' + (props ?
'<b>' + props.name + '</b><br />' + props.data + ' ratio'
: 'Hover over a country');
};
info.addTo(map);
function getColor(d) {
return d > 90 ? '#4a1486' :
d > 75 ? '#6a51a3' :
d > 50 ? '#807dba' :
d > 25 ? '#9e9ac8' :
d > 15 ? '#bcbddc' :
d > 5 ? '#dadaeb' :
d > 1 ? '#f2f0f7' :
'#D3D3D3'; // Default color of data doesn't exist or is 0.
}
function style(feature) {
return {
weight: 2,
opacity: 1,
color: 'white',
fillOpacity: 1,
fillColor: getColor(feature.properties.data)
};
}
function highlightFeature(e) {
let layer = e.target;
layer.setStyle({
weight: 5,
color: '#666',
fillOpacity: 0.7
});
if (!L.Browser.ie && !L.Browser.opera && !L.Browser.edge) {
layer.bringToFront();
}
info.update(layer.feature.properties);
}
let geojson;
function resetHighlight(e) {
geojson.resetStyle(e.target);
info.update();
}
function zoomToFeature(e) {
map.fitBounds(e.target.getBounds());
}
function onEachFeature(feature, layer) {
layer.on({
mouseover: highlightFeature,
mouseout: resetHighlight,
click: zoomToFeature
});
}
geojson = L.geoJson(countries, { // from import
style: style,
onEachFeature: onEachFeature
}).addTo(map);
let legend = L.control({position: 'bottomright'});
legend.onAdd = function (map) {
let div = L.DomUtil.create('div', 'info legend'),
grades = [1, 5, 15, 25, 50, 75, 90],
labels = [],
from, to;
for (let i = 0; i < grades.length; i++) {
from = grades[i];
to = grades[i + 1];
labels.push(
'<i style="background:' + getColor(from + 1) + '"></i> ' +
from + (to ? '–' + to : '+'));
}
div.innerHTML = labels.join('<br>');
return div;
};
legend.addTo(map);
});
}
});
export default Worldmap
如何强制leaflet在接收到新的this.props.data
时重新绘制或刷新地图?
我尝试使用componentDidUpdate
,在其中我基本上会执行map.remove()
,但是我遇到了不同组件之间的作用域问题.. 它都加载在componentDidMount
中,如果再次调用leaflet地图,它将显示已经初始化。
if (nextProps.data !== this.props.data) { youMapRef.clearLayers(); }
- Alex Parij