Gestire gli eventi del mouse

Seleziona la piattaforma: iOS JavaScript

Panoramica

Fai in modo che un livello di caratteristiche risponda agli eventi mousemove e click e usa per restituire informazioni sul confine su cui è stato fatto clic. Queste informazioni include ID, nome visualizzato e tipo di caratteristica. La mappa di esempio seguente mostra confini per il livello 2 dell'area amministrativa e dispone di un codice per la gestione degli eventi che stili i poligoni in base all'interazione dell'utente (mousemove cambia il bordo spessore massimo, click sfuma il colore di sfondo e attiva una finestra informativa display).

Abilita eventi a livello di caratteristiche

Per attivare gli eventi a livello di funzionalità, procedi nel seguente modo:

1. Registra un livello di funzionalità per le notifiche degli eventi richiamando il metodo addListener() nel livello delle caratteristiche per ogni evento che vuoi registro. In questo esempio la mappa riceve anche un listener.

   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;
     }
   });
   index.ts

   Nota: leggi la guida sull'utilizzo di TypeScript e Google Maps.

   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;
     }
   });
   index.js

2. Aggiungi il codice del gestore di eventi per definire lo stile del poligono selezionato in base al tipo di un'interazione.

   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;
   }
   index.ts

   Nota: leggi la guida sull'utilizzo di TypeScript e Google Maps.

   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;
   }
   index.js

3. Utilizza una funzione di stile delle caratteristiche per applicare gli stili. La funzione di stile delle caratteristiche mostrato qui applica lo stile in modo condizionale in base al tipo di interazione. Tre. gli stili sono definiti qui: uno per applicare il bordo in grassetto su mousemove, uno per cambia lo sfondo e mostra una finestra informativa su click e uno stile predefinito.

   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;
   }
   index.ts

   Nota: leggi la guida sull'utilizzo di TypeScript e Google Maps.

   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;
   }
   index.js

Nota: poiché è possibile interagire solo con le funzionalità visibili, il riempimento predefinito deve avere un valore fillOpacity pari o superiore a 0,1.

Codice di esempio completo

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();
index.ts

Nota: leggi la guida sull'utilizzo di TypeScript e Google Maps.

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();
index.js

Nota:il codice JavaScript viene compilato dallo snippet TypeScript.

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;
}
style.css

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>
index.html

Prova Sample

JSFiddle.net Google Cloud Shell

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