自动居中和自动缩放我的谷歌 API 地图答案

【问题标题】：Auto Centering and Auto Zoom my google API map自动居中和自动缩放我的谷歌 API 地图
【发布时间】：2020-04-13 06:23:43
【问题描述】：

好吧，与其让用户手动将经度和纬度设置为 -33.863276、151.207977 以使地图居中，您将如何使用 XML 文件中的点自动将其居中？我已经看到使用 bounds 函数来自动设置地图。但是，当我不使用增量时，我不确定如何使用 fitBounds 函数将其设置为正确的中心。您能否告诉我如何根据标记位置自动居中，同时尽可能少地更改代码。

              <!DOCTYPE html >
<head>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
<meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
<title>Using MySQL and PHP with Google Maps</title>
<style>
  /* 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>
</head>

<html>
<body>
<div id="map"></div>

<script>
  var customLabel = {
    restaurant: {
      label: 'R'
    },
    bar: {
      label: 'B'
    }
  };

    function initMap() {
    var map = new google.maps.Map(document.getElementById('map'), {
      center: new google.maps.LatLng(-33.863276, 151.207977),
      zoom: 12
    });
    var infoWindow = new google.maps.InfoWindow;

      // Change this depending on the name of your PHP or XML file
      downloadUrl('https://storage.googleapis.com/mapsdevsite/json/mapmarkers2.xml', function(data) {
        var xml = data.responseXML;
        var markers = xml.documentElement.getElementsByTagName('marker');
        Array.prototype.forEach.call(markers, function(markerElem) {
          var id = markerElem.getAttribute('id');
          var name = markerElem.getAttribute('name');
          var address = markerElem.getAttribute('address');
          var type = markerElem.getAttribute('type');
          var point = new google.maps.LatLng(
              parseFloat(markerElem.getAttribute('lat')),
              parseFloat(markerElem.getAttribute('lng')));

          var infowincontent = document.createElement('div');
          var strong = document.createElement('strong');
          strong.textContent = name
          infowincontent.appendChild(strong);
          infowincontent.appendChild(document.createElement('br'));

          var text = document.createElement('text');
          text.textContent = address
          infowincontent.appendChild(text);
          var icon = customLabel[type] || {};
          var marker = new google.maps.Marker({
            map: map,
            position: point,
            label: icon.label
          });
          marker.addListener('click', function() {
            infoWindow.setContent(infowincontent);
            infoWindow.open(map, marker);
          });
        });
      });
    }



  function downloadUrl(url, callback) {
    var request = window.ActiveXObject ?
        new ActiveXObject('Microsoft.XMLHTTP') :
        new XMLHttpRequest;

    request.onreadystatechange = function() {
      if (request.readyState == 4) {
        request.onreadystatechange = doNothing;
        callback(request, request.status);
      }
    };

    request.open('GET', url, true);
    request.send(null);
  }

  function doNothing() {}
</script>
<script async defer
src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap">
    </script>
  </body>
</html>

【问题讨论】：

标签： javascript html google-maps google-maps-api-3 location

【解决方案1】：

一个选项：调用将每个标记添加到边界，调用fitBounds(bounds)：

downloadUrl('https://storage.googleapis.com/mapsdevsite/json/mapmarkers2.xml', function(data) {
    var xml = data.responseXML;
    var markers = xml.documentElement.getElementsByTagName('marker');
    var bounds = new google.maps.LatLngBounds(); // create the bounds object
    Array.prototype.forEach.call(markers, function(markerElem) {
      var id = markerElem.getAttribute('id');
      var name = markerElem.getAttribute('name');
      var address = markerElem.getAttribute('address');
      var type = markerElem.getAttribute('type');
      var point = new google.maps.LatLng(
          parseFloat(markerElem.getAttribute('lat')),
          parseFloat(markerElem.getAttribute('lng')));

      var infowincontent = document.createElement('div');
      var strong = document.createElement('strong');
      strong.textContent = name
      infowincontent.appendChild(strong);
      infowincontent.appendChild(document.createElement('br'));

      var text = document.createElement('text');
      text.textContent = address
      infowincontent.appendChild(text);
      var icon = customLabel[type] || {};
      var marker = new google.maps.Marker({
        map: map,
        position: point,
        label: icon.label
      });
      bounds.extend(marker.getPosition()); // add the marker's position to the bounds
      map.fitBounds(bounds);               // call map.fitBounds
      marker.addListener('click', function() {
        infoWindow.setContent(infowincontent);
        infoWindow.open(map, marker);
      });
    });
  });
}

【讨论】：