概览
您可以让地图项图层响应 mousemove 和 click 事件,并使用它们返回所点击边界的相关信息。此信息包括 ID、显示名称和地图项类型。下面这个示例地图展示了 2 级行政区的边界,该地图使用了事件处理代码,用于根据用户互动为多边形应用样式(mousemove 更改边框粗细,click 为背景颜色着色并导致信息窗口显示)。
启用地图项图层事件
如果要在地图项图层上启用事件,请按以下步骤操作:
在地图项图层上为每个要注册的事件调用
addListener()函数,从而为地图项图层注册事件通知。在本示例中,地图还获得了一个监听器。TypeScript
// Add the feature layer. featureLayer = innerMap.getFeatureLayer( google.maps.FeatureType.ADMINISTRATIVE_AREA_LEVEL_2 ); // Add the event listeners for the feature layer. featureLayer.addListener('click', handleClick); featureLayer.addListener('mousemove', handleMouseMove); // Map event listener. innerMap.addListener('mousemove', () => { // If the map gets a mousemove, that means there are no feature layers // with listeners registered under the mouse, so we clear the last // interacted feature ids. if (lastInteractedFeatureIds?.length) { lastInteractedFeatureIds = []; featureLayer.style = applyStyle; } });
JavaScript
// Add the feature layer. featureLayer = innerMap.getFeatureLayer(google.maps.FeatureType.ADMINISTRATIVE_AREA_LEVEL_2); // Add the event listeners for the feature layer. featureLayer.addListener('click', handleClick); featureLayer.addListener('mousemove', handleMouseMove); // Map event listener. innerMap.addListener('mousemove', () => { // If the map gets a mousemove, that means there are no feature layers // with listeners registered under the mouse, so we clear the last // interacted feature ids. if (lastInteractedFeatureIds?.length) { lastInteractedFeatureIds = []; featureLayer.style = applyStyle; } });
添加事件处理脚本代码,以便根据互动类型为所选多边形设置样式。
TypeScript
function handleClick(/* MouseEvent */ e) { lastClickedFeatureIds = e.features.map((f) => f.placeId); lastInteractedFeatureIds = []; featureLayer.style = applyStyle; createInfoWindow(e); } function handleMouseMove(/* MouseEvent */ e) { lastInteractedFeatureIds = e.features.map((f) => f.placeId); featureLayer.style = applyStyle; }
JavaScript
function handleClick(/* MouseEvent */ e) { lastClickedFeatureIds = e.features.map((f) => f.placeId); lastInteractedFeatureIds = []; featureLayer.style = applyStyle; createInfoWindow(e); } function handleMouseMove(/* MouseEvent */ e) { lastInteractedFeatureIds = e.features.map((f) => f.placeId); featureLayer.style = applyStyle; }
使用地图项样式函数来应用样式。此处显示的地图项样式函数会根据互动类型有条件地应用样式。此处定义了三种样式:一种用于在
mousemove时加粗边框,一种用于在click时更改背景并显示信息窗口,还有一种是默认样式。TypeScript
// Define styles. // Stroke and fill with minimum opacity value. const styleDefault = { strokeColor: '#810FCB', strokeOpacity: 1.0, strokeWeight: 2.0, fillColor: 'white', fillOpacity: 0.1, // Polygons must be visible to receive events. }; // Style for the clicked polygon. const styleClicked = { ...styleDefault, fillColor: '#810FCB', fillOpacity: 0.5, }; // Style for polygon on mouse move. const styleMouseMove = { ...styleDefault, strokeWeight: 4.0, }; // Apply styles using a feature style function. function applyStyle(/* FeatureStyleFunctionOptions */ params) { const placeId = params.feature.placeId; //@ts-ignore if (lastClickedFeatureIds.includes(placeId)) { return styleClicked; } //@ts-ignore if (lastInteractedFeatureIds.includes(placeId)) { return styleMouseMove; } return styleDefault; }
JavaScript
// Define styles. // Stroke and fill with minimum opacity value. const styleDefault = { strokeColor: '#810FCB', strokeOpacity: 1.0, strokeWeight: 2.0, fillColor: 'white', fillOpacity: 0.1, // Polygons must be visible to receive events. }; // Style for the clicked polygon. const styleClicked = { ...styleDefault, fillColor: '#810FCB', fillOpacity: 0.5, }; // Style for polygon on mouse move. const styleMouseMove = { ...styleDefault, strokeWeight: 4.0, }; // Apply styles using a feature style function. function applyStyle(/* FeatureStyleFunctionOptions */ params) { const placeId = params.feature.placeId; //@ts-ignore if (lastClickedFeatureIds.includes(placeId)) { return styleClicked; } //@ts-ignore if (lastInteractedFeatureIds.includes(placeId)) { return styleMouseMove; } return styleDefault; }
完整示例代码
TypeScript
let innerMap; let featureLayer; let infoWindow; let lastInteractedFeatureIds = []; let lastClickedFeatureIds = []; function handleClick(/* MouseEvent */ e) { lastClickedFeatureIds = e.features.map((f) => f.placeId); lastInteractedFeatureIds = []; featureLayer.style = applyStyle; createInfoWindow(e); } function handleMouseMove(/* MouseEvent */ e) { lastInteractedFeatureIds = e.features.map((f) => f.placeId); featureLayer.style = applyStyle; } async function initMap() { // Request needed libraries. const { Map, InfoWindow } = (await google.maps.importLibrary( 'maps' )) as google.maps.MapsLibrary; // Get the gmp-map element. const mapElement = document.querySelector( 'gmp-map' ) as google.maps.MapElement; // Get the inner map. innerMap = mapElement.innerMap; // Set map options. innerMap.setOptions({ mapTypeControl: false, }); // Add the feature layer. featureLayer = innerMap.getFeatureLayer( google.maps.FeatureType.ADMINISTRATIVE_AREA_LEVEL_2 ); // Add the event listeners for the feature layer. featureLayer.addListener('click', handleClick); featureLayer.addListener('mousemove', handleMouseMove); // Map event listener. innerMap.addListener('mousemove', () => { // If the map gets a mousemove, that means there are no feature layers // with listeners registered under the mouse, so we clear the last // interacted feature ids. if (lastInteractedFeatureIds?.length) { lastInteractedFeatureIds = []; featureLayer.style = applyStyle; } }); // Create the infowindow. infoWindow = new InfoWindow({}); // Apply style on load, to enable clicking. featureLayer.style = applyStyle; } // Helper function for the infowindow. async function createInfoWindow(event) { let feature = event.features[0]; if (!feature.placeId) return; // Update the info window. // Get the place instance from the selected feature. const place = await feature.fetchPlace(); // Create a new div to hold the text content. let content = document.createElement('div'); // Get the text values. let nameText = document.createElement('span'); nameText.textContent = `Display name: ${place.displayName}`; let placeIdText = document.createElement('span'); placeIdText.textContent = `Place ID: ${feature.placeId}`; let featureTypeText = document.createElement('span'); featureTypeText.textContent = `Feature type: ${feature.featureType}`; // Append the text to the div. content.appendChild(nameText); content.appendChild(document.createElement('br')); content.appendChild(placeIdText); content.appendChild(document.createElement('br')); content.appendChild(featureTypeText); updateInfoWindow(content, event.latLng); } // Define styles. // Stroke and fill with minimum opacity value. const styleDefault = { strokeColor: '#810FCB', strokeOpacity: 1.0, strokeWeight: 2.0, fillColor: 'white', fillOpacity: 0.1, // Polygons must be visible to receive events. }; // Style for the clicked polygon. const styleClicked = { ...styleDefault, fillColor: '#810FCB', fillOpacity: 0.5, }; // Style for polygon on mouse move. const styleMouseMove = { ...styleDefault, strokeWeight: 4.0, }; // Apply styles using a feature style function. function applyStyle(/* FeatureStyleFunctionOptions */ params) { const placeId = params.feature.placeId; //@ts-ignore if (lastClickedFeatureIds.includes(placeId)) { return styleClicked; } //@ts-ignore if (lastInteractedFeatureIds.includes(placeId)) { return styleMouseMove; } return styleDefault; } // Helper function to create an info window. function updateInfoWindow(content, center) { infoWindow.setContent(content); infoWindow.setPosition(center); infoWindow.open({ map: innerMap, shouldFocus: false, }); } initMap();
JavaScript
let innerMap; let featureLayer; let infoWindow; let lastInteractedFeatureIds = []; let lastClickedFeatureIds = []; function handleClick(/* MouseEvent */ e) { lastClickedFeatureIds = e.features.map((f) => f.placeId); lastInteractedFeatureIds = []; featureLayer.style = applyStyle; createInfoWindow(e); } function handleMouseMove(/* MouseEvent */ e) { lastInteractedFeatureIds = e.features.map((f) => f.placeId); featureLayer.style = applyStyle; } async function initMap() { // Request needed libraries. const { Map, InfoWindow } = (await google.maps.importLibrary('maps')); // Get the gmp-map element. const mapElement = document.querySelector('gmp-map'); // Get the inner map. innerMap = mapElement.innerMap; // Set map options. innerMap.setOptions({ mapTypeControl: false, }); // Add the feature layer. featureLayer = innerMap.getFeatureLayer(google.maps.FeatureType.ADMINISTRATIVE_AREA_LEVEL_2); // Add the event listeners for the feature layer. featureLayer.addListener('click', handleClick); featureLayer.addListener('mousemove', handleMouseMove); // Map event listener. innerMap.addListener('mousemove', () => { // If the map gets a mousemove, that means there are no feature layers // with listeners registered under the mouse, so we clear the last // interacted feature ids. if (lastInteractedFeatureIds?.length) { lastInteractedFeatureIds = []; featureLayer.style = applyStyle; } }); // Create the infowindow. infoWindow = new InfoWindow({}); // Apply style on load, to enable clicking. featureLayer.style = applyStyle; } // Helper function for the infowindow. async function createInfoWindow(event) { let feature = event.features[0]; if (!feature.placeId) return; // Update the info window. // Get the place instance from the selected feature. const place = await feature.fetchPlace(); // Create a new div to hold the text content. let content = document.createElement('div'); // Get the text values. let nameText = document.createElement('span'); nameText.textContent = `Display name: ${place.displayName}`; let placeIdText = document.createElement('span'); placeIdText.textContent = `Place ID: ${feature.placeId}`; let featureTypeText = document.createElement('span'); featureTypeText.textContent = `Feature type: ${feature.featureType}`; // Append the text to the div. content.appendChild(nameText); content.appendChild(document.createElement('br')); content.appendChild(placeIdText); content.appendChild(document.createElement('br')); content.appendChild(featureTypeText); updateInfoWindow(content, event.latLng); } // Define styles. // Stroke and fill with minimum opacity value. const styleDefault = { strokeColor: '#810FCB', strokeOpacity: 1.0, strokeWeight: 2.0, fillColor: 'white', fillOpacity: 0.1, // Polygons must be visible to receive events. }; // Style for the clicked polygon. const styleClicked = { ...styleDefault, fillColor: '#810FCB', fillOpacity: 0.5, }; // Style for polygon on mouse move. const styleMouseMove = { ...styleDefault, strokeWeight: 4.0, }; // Apply styles using a feature style function. function applyStyle(/* FeatureStyleFunctionOptions */ params) { const placeId = params.feature.placeId; //@ts-ignore if (lastClickedFeatureIds.includes(placeId)) { return styleClicked; } //@ts-ignore if (lastInteractedFeatureIds.includes(placeId)) { return styleMouseMove; } return styleDefault; } // Helper function to create an info window. function updateInfoWindow(content, center) { infoWindow.setContent(content); infoWindow.setPosition(center); infoWindow.open({ map: innerMap, shouldFocus: false, }); } initMap();
CSS
/* * Always set the map height explicitly to define the size of the div element * that contains the map. */ gmp-map { height: 100%; } /* * Optional: Makes the sample page fill the window. */ html, body { height: 100%; margin: 0; padding: 0; }
HTML
<html>
<head>
<title>Handle Region Boundary Click Event</title>
<link rel="stylesheet" type="text/css" href="./style.css" />
<script type="module" src="./index.js"></script>
<!-- prettier-ignore -->
<script>(g=>{var h,a,k,p="The Google Maps JavaScript API",c="google",l="importLibrary",q="__ib__",m=document,b=window;b=b[c]||(b[c]={});var d=b.maps||(b.maps={}),r=new Set,e=new URLSearchParams,u=()=>h||(h=new Promise(async(f,n)=>{await (a=m.createElement("script"));e.set("libraries",[...r]+"");for(k in g)e.set(k.replace(/[A-Z]/g,t=>"_"+t[0].toLowerCase()),g[k]);e.set("callback",c+".maps."+q);a.src=`https://maps.${c}apis.com/maps/api/js?`+e;d[q]=f;a.onerror=()=>h=n(Error(p+" could not load."));a.nonce=m.querySelector("script[nonce]")?.nonce||"";m.head.append(a)}));d[l]?console.warn(p+" only loads once. Ignoring:",g):d[l]=(f,...n)=>r.add(f)&&u().then(()=>d[l](f,...n))})
({key: "AIzaSyA6myHzS10YXdcazAFalmXvDkrYCp5cLc8", v: "weekly"});</script>
</head>
<body>
<gmp-map center="39.23,-105.73" zoom="8" map-id="8b37d7206ccf0121a2634fd5">
</body>
</html>