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Listening to Events

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Page Summary

This example demonstrates creating a user-editable, draggable rectangle on a Google Map.
An info window dynamically displays the updated coordinates of the rectangle's northeast and southwest corners as the user adjusts it.
The sample code utilizes the Google Maps JavaScript API with event listeners and the Rectangle class to achieve this functionality.
You can interact with a live version of this example via JSFiddle or Google Cloud Shell, or clone and run the sample locally using Git and Node.js.

This example adds a user-editable rectangle to the map. When the user changes the bounds of the rectangle, an info window pops up displaying the new bounds.

Read the documentation.

[フレーム]

TypeScript

// This example adds a user-editable rectangle to the map.
// When the user changes the bounds of the rectangle,
// an info window pops up displaying the new bounds.
letrectangle:google.maps.Rectangle;
letinnerMap:google.maps.Map;
letinfoWindow:google.maps.InfoWindow;
asyncfunctioninit():Promise<void>{
const{Rectangle,InfoWindow}=awaitgoogle.maps.importLibrary('maps');
constmapElement=document.querySelector('gmp-map')!;
innerMap=mapElement.innerMap;
constbounds={
north:44.599,
south:44.49,
east:-78.443,
west:-78.649,
};
// Define the rectangle and set its editable property to true.
rectangle=newRectangle({
bounds,
editable:true,
draggable:true,
});
rectangle.setMap(innerMap);
// Add an event listener on the rectangle.
rectangle.addListener('bounds_changed',showNewRect);
// Define an info window on the map.
infoWindow=newInfoWindow();
}
/** Show the new coordinates for the rectangle in an info window. */
functionshowNewRect(){
constne=rectangle.getBounds()!.getNorthEast();
constsw=rectangle.getBounds()!.getSouthWest();
constcontentString=
'<b>Rectangle moved.</b><br>'+
'New north-east corner: '+
ne.lat()+
', '+
ne.lng()+
'<br>'+
'New south-west corner: '+
sw.lat()+
', '+
sw.lng();
// Set the info window's content and position.
infoWindow.setContent(contentString);
infoWindow.setPosition(ne);
infoWindow.open(innerMap);
}
voidinit();index.ts

JavaScript

// This example adds a user-editable rectangle to the map.
// When the user changes the bounds of the rectangle,
// an info window pops up displaying the new bounds.
letrectangle;
letinnerMap;
letinfoWindow;
asyncfunctioninit(){
const{Rectangle,InfoWindow}=awaitgoogle.maps.importLibrary('maps');
constmapElement=document.querySelector('gmp-map');
innerMap=mapElement.innerMap;
constbounds={
north:44.599,
south:44.49,
east:-78.443,
west:-78.649,
};
// Define the rectangle and set its editable property to true.
rectangle=newRectangle({
bounds,
editable:true,
draggable:true,
});
rectangle.setMap(innerMap);
// Add an event listener on the rectangle.
rectangle.addListener('bounds_changed',showNewRect);
// Define an info window on the map.
infoWindow=newInfoWindow();
}
/** Show the new coordinates for the rectangle in an info window. */
functionshowNewRect(){
constne=rectangle.getBounds().getNorthEast();
constsw=rectangle.getBounds().getSouthWest();
constcontentString=
'<b>Rectangle moved.</b><br>'+
'New north-east corner: '+
ne.lat()+
', '+
ne.lng()+
'<br>'+
'New south-west corner: '+
sw.lat()+
', '+
sw.lng();
// Set the info window's content and position.
infoWindow.setContent(contentString);
infoWindow.setPosition(ne);
infoWindow.open(innerMap);
}
voidinit();index.js

CSS

/* 
 * Optional: Makes the sample page fill the window. 
 */
html,
body{
height:100%;
margin:0;
padding:0;
}
style.css

HTML

<html>
 <head>
 <title>Listening to Events</title>
 <link rel="stylesheet" type="text/css" href="./style.css" />
 <script type="module" src="./index.js"></script>
 <script>
 // prettier-ignore
 (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: "GOOGLE_MAPS_API_KEY"
 });
 </script>
 </head>
 <body>
 <gmp-map
 center="44.5452,-78.5389"
 zoom="9"
 map-id="DEMO_MAP_ID"></gmp-map>
 </body>
</html>index.html

Clone Sample

Git and Node.js are required to run this sample locally. Follow these instructions to install Node.js and NPM. The following commands clone, install dependencies and start the sample application.

gitclonehttps://github.com/googlemaps-samples/js-api-samples.git
cdsamples/rectangle-event
npmi
npmstart