Mausereignisse verarbeiten

Plattform auswählen: Android iOS JavaScript

Übersicht

Sie können eine Feature-Ebene so konfigurieren, dass auf mousemove- und click-Ereignisse reagiert wird, um Informationen zur angeklickten Grenze zurückzugeben. Diese Informationen umfassen ID, Anzeigename und Elementtyp. Auf der folgenden Beispielkarte sehen Sie Grenzen für Verwaltungsgebiete der Stufe 2. Sie enthält Event-Handler-Code, mit dem Polygone basierend auf Nutzerinteraktionen formatiert werden (mousemove ändert die Strichstärke der Umrandung, click schattiert die Hintergrundfarbe und bewirkt, dass ein Infofenster angezeigt wird).

Ereignisse auf Feature-Ebene aktivieren

So aktivieren Sie Ereignisse auf Feature-Ebene:

  1. Um eine Feature-Ebene für Ereignisbenachrichtigungen zu registrieren, rufen Sie die Funktion addListener() für die Feature-Ebene für jedes Ereignis auf, das Sie registrieren möchten. In diesem Beispiel wird der Karte auch ein Listener hinzugefügt.

    TypeScript

    // Add the feature layer.
    //@ts-ignore
    featureLayer = map.getFeatureLayer('ADMINISTRATIVE_AREA_LEVEL_2');
    
    // Add the event listeners for the feature layer.
    featureLayer.addListener('click', handleClick);
    featureLayer.addListener('mousemove', handleMouseMove);
    
    // Map event listener.
    map.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.
    //@ts-ignore
    featureLayer = map.getFeatureLayer("ADMINISTRATIVE_AREA_LEVEL_2");
    // Add the event listeners for the feature layer.
    featureLayer.addListener("click", handleClick);
    featureLayer.addListener("mousemove", handleMouseMove);
    // Map event listener.
    map.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;
      }
    });

  2. Fügen Sie Event-Handler-Code hinzu, um das ausgewählte Polygon basierend auf der Art der Interaktion zu gestalten.

    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;
    }
    

  3. Mit einer Stilfunktion für Elemente können Sie Stile anwenden. Die hier gezeigte Stilfunktion für Elemente wendet den Stil bedingt auf den Interaktionstyp an. Hier sind drei Stile definiert: einer, um den Rahmen auf mousemove fett darzustellen, einer, um den Hintergrund zu ändern und ein Infofenster auf click anzuzeigen, und ein Standardstil.

    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;
    }
    

Vollständiges Codebeispiel

TypeScript

let map: google.maps.Map;
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;

  map = new Map(document.getElementById('map') as HTMLElement, {
    center: {lat: 39.23, lng: -105.73},
    zoom: 8,
    // In the cloud console, configure your Map ID with a style that enables the
    // 'Administrative Area Level 2' Data Driven Styling type.
    mapId: 'a3efe1c035bad51b', // Substitute your own map ID.
    mapTypeControl: false,
  });

  // Add the feature layer.
  //@ts-ignore
  featureLayer = map.getFeatureLayer('ADMINISTRATIVE_AREA_LEVEL_2');

  // Add the event listeners for the feature layer.
  featureLayer.addListener('click', handleClick);
  featureLayer.addListener('mousemove', handleMouseMove);

  // Map event listener.
  map.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 infowindow.
  const place = await feature.fetchPlace();
  let content =
      '<span style="font-size:small">Display name: ' + place.displayName +
      '<br/> Place ID: ' + feature.placeId +
      '<br/> Feature type: ' + feature.featureType + '</span>';

  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,
    shouldFocus: false,
  });
}

initMap();

JavaScript

let map;
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");

  map = new Map(document.getElementById("map"), {
    center: { lat: 39.23, lng: -105.73 },
    zoom: 8,
    // In the cloud console, configure your Map ID with a style that enables the
    // 'Administrative Area Level 2' Data Driven Styling type.
    mapId: "a3efe1c035bad51b", // Substitute your own map ID.
    mapTypeControl: false,
  });
  // Add the feature layer.
  //@ts-ignore
  featureLayer = map.getFeatureLayer("ADMINISTRATIVE_AREA_LEVEL_2");
  // Add the event listeners for the feature layer.
  featureLayer.addListener("click", handleClick);
  featureLayer.addListener("mousemove", handleMouseMove);
  // Map event listener.
  map.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 infowindow.
  const place = await feature.fetchPlace();
  let content =
    '<span style="font-size:small">Display name: ' +
    place.displayName +
    "<br/> Place ID: " +
    feature.placeId +
    "<br/> Feature type: " +
    feature.featureType +
    "</span>";

  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,
    shouldFocus: false,
  });
}

initMap();

CSS

/* 
 * Always set the map height explicitly to define the size of the div element
 * that contains the map. 
 */
#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>
  </head>
  <body>
    <div id="map"></div>

    <!-- 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: "AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg", v: "weekly"});</script>
  </body>
</html>

Testbeispiel

Weitere Informationen zu Ereignissen