谷歌地圖v3的設置與編輯半徑的圓，但不居中

Question

我已成功地把一個圓圈在地圖上，並使其可編輯：

var circle = new google.maps.Circle({ 
      map: map, 
      radius: 1609.344, // 1 mile 
      editable: true, 
      fillOpacity: 0.25 
     }); 


circle.bindTo('center', marker, 'position'); 

然而，這使得無論是半徑，中心編輯。我只希望半徑是可編輯的。我看不到通過google.maps.Circle來控制這種控制級別的方法。

我什麼之後，幾乎是什麼是在這裏：

http://www.freemaptools.com/radius-around-point.htm

不過，我看不出它是如何爲他們的代碼看起來混淆完成。

Answer 1

請參閱文檔中的this article（可編輯對象之前）。如果你採用step 6並且不要讓中心標記可拖動，我認爲這是你想要的。

fiddle containing original code from link

代碼片段：

/** 
 
* A distance widget that will display a circle that can be resized and will 
 
* provide the radius in km. 
 
* 
 
* @param {google.maps.Map} map The map to attach to. 
 
* 
 
* @constructor 
 
*/ 
 
function DistanceWidget(map) { 
 
    this.set('map', map); 
 
    this.set('position', map.getCenter()); 
 

 
    var marker = new google.maps.Marker({ 
 
    // draggable: true, // <-- change to make so position doesn't move 
 
    title: 'Move me!' 
 
    }); 
 

 
    // Bind the marker map property to the DistanceWidget map property 
 
    marker.bindTo('map', this); 
 

 
    // Bind the marker position property to the DistanceWidget position 
 
    // property 
 
    marker.bindTo('position', this); 
 

 
    // Create a new radius widget 
 
    var radiusWidget = new RadiusWidget(); 
 

 
    // Bind the radiusWidget map to the DistanceWidget map 
 
    radiusWidget.bindTo('map', this); 
 

 
    // Bind the radiusWidget center to the DistanceWidget position 
 
    radiusWidget.bindTo('center', this, 'position'); 
 

 
    // Bind to the radiusWidgets' distance property 
 
    this.bindTo('distance', radiusWidget); 
 

 
    // Bind to the radiusWidgets' bounds property 
 
    this.bindTo('bounds', radiusWidget); 
 
} 
 
DistanceWidget.prototype = new google.maps.MVCObject(); 
 

 

 
/** 
 
* A radius widget that add a circle to a map and centers on a marker. 
 
* 
 
* @constructor 
 
*/ 
 
function RadiusWidget() { 
 
    var circle = new google.maps.Circle({ 
 
    strokeWeight: 2 
 
    }); 
 

 
    // Set the distance property value, default to 10km. 
 
    this.set('distance', 10); 
 

 
    // Bind the RadiusWidget bounds property to the circle bounds property. 
 
    this.bindTo('bounds', circle); 
 

 
    // Bind the circle center to the RadiusWidget center property 
 
    circle.bindTo('center', this); 
 

 
    // Bind the circle map to the RadiusWidget map 
 
    circle.bindTo('map', this); 
 

 
    // Bind the circle radius property to the RadiusWidget radius property 
 
    circle.bindTo('radius', this); 
 

 
    // Add the sizer marker 
 
    this.addSizer_(); 
 
} 
 
RadiusWidget.prototype = new google.maps.MVCObject(); 
 

 

 
/** 
 
* Update the radius when the distance has changed. 
 
*/ 
 
RadiusWidget.prototype.distance_changed = function() { 
 
    this.set('radius', this.get('distance') * 1000); 
 
}; 
 

 

 
/** 
 
* Add the sizer marker to the map. 
 
* 
 
* @private 
 
*/ 
 
RadiusWidget.prototype.addSizer_ = function() { 
 
    var sizer = new google.maps.Marker({ 
 
    draggable: true, 
 
    title: 'Drag me!' 
 
    }); 
 

 
    sizer.bindTo('map', this); 
 
    sizer.bindTo('position', this, 'sizer_position'); 
 

 
    var me = this; 
 
    google.maps.event.addListener(sizer, 'drag', function() { 
 
    // As the sizer is being dragged, its position changes. Because the 
 
    // RadiusWidget's sizer_position is bound to the sizer's position, it will 
 
    // change as well. 
 
    var min = 0.5; 
 
    var max = 15; 
 
    var pos = me.get('sizer_position'); 
 
    var center = me.get('center'); 
 
    var distance = google.maps.geometry.spherical.computeDistanceBetween(center, pos)/1000; 
 
    if (distance < min) { 
 
     me.set('sizer_position', google.maps.geometry.spherical.computeOffset(center, min * 1000, google.maps.geometry.spherical.computeHeading(center, pos))); 
 
    } else if (distance > max) { 
 
     me.set('sizer_position', google.maps.geometry.spherical.computeOffset(center, max * 1000, google.maps.geometry.spherical.computeHeading(center, pos))); 
 
    } 
 
    // Set the circle distance (radius) 
 
    me.setDistance(); 
 
    }); 
 
}; 
 

 

 
/** 
 
* Update the center of the circle and position the sizer back on the line. 
 
* 
 
* Position is bound to the DistanceWidget so this is expected to change when 
 
* the position of the distance widget is changed. 
 
*/ 
 
RadiusWidget.prototype.center_changed = function() { 
 
    var bounds = this.get('bounds'); 
 

 
    // Bounds might not always be set so check that it exists first. 
 
    if (bounds) { 
 
    var lng = bounds.getNorthEast().lng(); 
 

 
    // Put the sizer at center, right on the circle. 
 
    var position = new google.maps.LatLng(this.get('center').lat(), lng); 
 
    this.set('sizer_position', position); 
 
    } 
 
}; 
 

 

 
/** 
 
* Set the distance of the circle based on the position of the sizer. 
 
*/ 
 
RadiusWidget.prototype.setDistance = function() { 
 
    // As the sizer is being dragged, its position changes. Because the 
 
    // RadiusWidget's sizer_position is bound to the sizer's position, it will 
 
    // change as well. 
 
    var pos = this.get('sizer_position'); 
 
    var center = this.get('center'); 
 
    var distance = google.maps.geometry.spherical.computeDistanceBetween(center, pos)/1000; 
 

 
    // Set the distance property for any objects that are bound to it 
 
    this.set('distance', distance); 
 
}; 
 

 

 
function init() { 
 
    var mapDiv = document.getElementById('map-canvas'); 
 
    var map = new google.maps.Map(mapDiv, { 
 
    center: new google.maps.LatLng(37.790234970864, -122.39031314844), 
 
    zoom: 11, 
 
    mapTypeId: google.maps.MapTypeId.ROADMAP 
 
    }); 
 
    var distanceWidget = new DistanceWidget(map); 
 

 
    google.maps.event.addListener(distanceWidget, 'distance_changed', function() { 
 
    displayInfo(distanceWidget); 
 
    }); 
 

 
    google.maps.event.addListener(distanceWidget, 'position_changed', function() { 
 
    displayInfo(distanceWidget); 
 
    }); 
 
} 
 

 
function displayInfo(widget) { 
 
    var info = document.getElementById('info'); 
 
    info.innerHTML = 'Position: ' + widget.get('position') + ', distance: ' + 
 
    widget.get('distance'); 
 
} 
 

 
google.maps.event.addDomListener(window, 'load', init);

#map-canvas { 
 
    height: 500px; 
 
}

<script src="https://maps.googleapis.com/maps/api/js?libraries=geometry"></script> 
 
<div id="info"></div> 
 
<div id="map-canvas"></div>

original article (link now dead)

Answer 2

您可以嘗試監聽center_changed的事件，火災時重新調整中心，例如：

全局變量：

var centerPoint = new G.LatLng(45.5, -100.5); 
    var ignore = false; 
    var poly; 
//position the map where the circle is so we can see it. 
    map.setCenter(centerPoint); 
    map.setZoom(11); 

然後：

poly = new google.maps.Circle({ 
    map: map, 
    center:centerPoint, 
    radius: 1609.344, // 1 mile 
    editable: true, 
    fillOpacity: 0.25 
}); 

G.event.addListener(poly,'center_changed',function(){ 
    if (ignore){ 
     ignore = false; 
     return; 
    } 
    poly.setEditable(false); 
    ignore = true; 
    poly.setCenter(centerPoint); 
    poly.setEditable(true); 
}); 

唯一的問題中心標記可能會誤導用戶。