javascript - 谷歌地图设置 DirectionsRenderer 对象的方向不绘制路线

尝试绘制路线时，代码运行正常，但不渲染。

下面是一个示例代码，其结构和行为方式相同:

<!DOCTYPE html>
<html>

<head>
  <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
  <meta charset="utf-8">
  <title>Simple markers</title>
  <style>    
    #map {
      height: 100%;
    }

    html,
    body {
      height: 100%;
      margin: 0;
      padding: 0;
    }
  </style>
</head>

<body>
  <div id="map"></div>
  <script>
    var routeDisplay = new function() {
      var self = this;
      // Variables
      self.directionsService;
      self.directionsRenderer;
      self.map;
      self.origin;
      self.destination;

      // Functions
      self.setup = function() {
        self.directionsService = new google.maps.DirectionsService();
        self.directionsRenderer = new google.maps.DirectionsRenderer({
          preserveViewport: true,
          suppressMarkers: true
        });
      }

      self.setMap = function(map) {
        self.map = map;
        self.directionsRenderer.map = map;
      }

      self.setPoints = function(origin, destination) {
        self.origin = origin;
        self.destination = destination;
      }

      self.render = function() {
        if (self.directionsRenderer.map == null) self.directionsRenderer.map = self.map;
        self.directionsService.route({
          origin: self.origin,
          destination: self.destination,
          travelMode: 'DRIVING'
        }, function(response, status) {
          if (status === 'OK') {
            self.directionsRenderer.setDirections(response);
          } else {
            window.alert('Directions request failed due to ' + status);
          }
        });
      }

      self.hide = function() {
        self.directionsRenderer.map = null;
      }

      self.show = function() {
        self.directionsRenderer.map = self.map;
      }

      self.toggleShow = function() {
        self.directionsRenderer.map = (self.directionsRenderer.map == null) ?
          self.map : null;
      }

      self.isAlreadyRendered = function(origin, destination) {
        if (origin == self.origin && destination == self.destination) return true;
        return false;
      }
    }

    function initMap() {
      var myLatLng = {
        lat: 45.5325016,
        lng: -122.7973512
      };

      var map = new google.maps.Map(document.getElementById('map'), {
        zoom: 15,
        center: myLatLng
      });

      var start = new google.maps.Marker({
        position: myLatLng,
        map: map,
        label: 'start'
      });

      var end = new google.maps.Marker({
        position: {
          lat: myLatLng.lat - .5,
          lng: myLatLng.lng - .5
        },
        map: map,
        label: 'end'
      });

      // Set up routeDisplay
      routeDisplay.setup();
      routeDisplay.setMap(map);

      start.addListener('click', function() {
        var a = start.position;
        var b = end.position;
        if (routeDisplay.isAlreadyRendered(a, b)) routeDisplay.toggleShow();
        else {
          routeDisplay.setPoints(a, b);
          routeDisplay.render();
        }
      });
    }
  </script>

  <script async defer src="https://maps.googleapis.com/maps/api/js?key=MY_API_KEY&callback=initMap">
  </script>
</body>

</html>

调用 directionsRenderer.setDirections(response) 应呈现路线，如 Google Maps API 文档所述:

Call setDirections() on the renderer, passing it the DirectionsResult as noted above. Because the renderer is an MVCObject, it will automatically detect any changes to its properties and update the map when its associated directions have changed.

这种确切的策略通常工作得很好，但在这种情况下，我的 self.render 函数是我用来处理所有路由渲染的对象内部的函数。

还应该注意的是，我已经确认 directionsRenderer 使用的 map 是正确的 map ，并且 directionRenderer.directions 确实发生了变化(正如它应该发生的那样)。

什么可能会阻止路线折线的渲染？

最佳答案

要设置 DirectionsRenderer 的 map 属性，请使用 .setMap 方法。您当前正在设置 DirectionsRenderer 的 map 属性，该属性未记录在案。

  var routeDisplay = new function() {
    var self = this;
    // Variables
    self.directionsService;
    self.directionsRenderer;
    self.map;
    self.origin;
    self.destination;

    // Functions
    self.setup = function() {
      self.directionsService = new google.maps.DirectionsService();
      self.directionsRenderer = new google.maps.DirectionsRenderer({
        preserveViewport: true,
        suppressMarkers: true
      });
    }

    self.setMap = function(map) {
      self.map = map;
      self.directionsRenderer.setMap(map);
    }

    self.setPoints = function(origin, destination) {
      self.origin = origin;
      self.destination = destination;
    }

    self.render = function() {
      if (self.directionsRenderer.getMap() == null)
        self.directionsRenderer.setMap(self.map);

      self.directionsService.route({
        origin: self.origin,
        destination: self.destination,
        travelMode: 'DRIVING'
      }, function(response, status) {
        if (status === 'OK') {
          self.directionsRenderer.setDirections(response);
        } else {
          window.alert('Directions request failed due to ' + status);
        }
      });
    }

    self.hide = function() {
      self.directionsRenderer.setMap(null);
    }

    self.show = function() {
      self.directionsRenderer.setMap(self.map);
    }

    self.toggleShow = function() {
      self.directionsRenderer.map = (self.directionsRenderer.getMap() == null) ?
        self.map : null;
    }

    self.isAlreadyRendered = function(origin, destination) {
      if (origin == self.origin && destination == self.destination) return true;
      return false;
    }
  }

proof of concept fiddle

代码片段:

html,
body,
#map {
  height: 100%;
  width: 100%;
  margin: 0px;
  padding: 0px
}

<div id="map"></div>
<script>
  var routeDisplay = new function() {
    var self = this;
    // Variables
    self.directionsService;
    self.directionsRenderer;
    self.map;
    self.origin;
    self.destination;

    // Functions
    self.setup = function() {
      self.directionsService = new google.maps.DirectionsService();
      self.directionsRenderer = new google.maps.DirectionsRenderer({
        preserveViewport: true,
        suppressMarkers: true
      });
    }

    self.setMap = function(map) {
      self.map = map;
      self.directionsRenderer.setMap(map);
    }

    self.setPoints = function(origin, destination) {
      self.origin = origin;
      self.destination = destination;
    }

    self.render = function() {
      if (self.directionsRenderer.getMap() == null)
        self.directionsRenderer.setMap(self.map);

      self.directionsService.route({
        origin: self.origin,
        destination: self.destination,
        travelMode: 'DRIVING'
      }, function(response, status) {
        if (status === 'OK') {
          self.directionsRenderer.setDirections(response);
        } else {
          window.alert('Directions request failed due to ' + status);
        }
      });
    }

    self.hide = function() {
      self.directionsRenderer.setMap(null);
    }

    self.show = function() {
      self.directionsRenderer.setMap(self.map);
    }

    self.toggleShow = function() {
      self.directionsRenderer.map = (self.directionsRenderer.getMap() == null) ?
        self.map : null;
    }

    self.isAlreadyRendered = function(origin, destination) {
      if (origin == self.origin && destination == self.destination) return true;
      return false;
    }
  }

  function initMap() {
    var myLatLng = {
      lat: 45.5325016,
      lng: -122.7973512
    };

    var map = new google.maps.Map(document.getElementById('map'), {
      zoom: 15,
      center: myLatLng
    });

    var start = new google.maps.Marker({
      position: myLatLng,
      map: map,
      label: 'start'
    });

    var end = new google.maps.Marker({
      position: {
        lat: myLatLng.lat - .5,
        lng: myLatLng.lng - .5
      },
      map: map,
      label: 'end'
    });

    // Set up routeDisplay
    routeDisplay.setup();
    routeDisplay.setMap(map);

    start.addListener('click', function() {
      var a = start.position;
      var b = end.position;
      if (routeDisplay.isAlreadyRendered(a, b)) routeDisplay.toggleShow();
      else {
        routeDisplay.setPoints(a, b);
        routeDisplay.render();
      }
    });
  }
</script>

<script async defer src="https://maps.googleapis.com/maps/api/js?callback=initMap&key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk">
</script>

关于javascript - 谷歌地图设置 DirectionsRenderer 对象的方向不绘制路线，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/51386741/

javascript - 谷歌地图设置 DirectionsRenderer 对象的方向不绘制路线

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