Openlayers自定义标记 [英] Openlayers Custom Marker

问题描述

一些信息:我得到了一个主层(地图)，并且我用Linestring在从JSON结果中获取的点之间绘制了线.

some info: I got a main layer (map) which and im drawing lines between points recived from a JSON result with a Linestring.

(问题)我在网上跟随一个示例，说明如何自定义要添加的点.但这是行不通的.(查看底部的功能.)

(issue) I followed an example online on how to customize the points i am adding. But this does not work. (Look at the function on the bottom.)

代码:

//'listOfPoints' is an array containing all the point objects.

var pointmap = new OpenLayers.Geometry.LineString(listOfPoints);

    var lastpoint = listOfPoints[listOfPoints.length -1];


    var vesselLayer = new OpenLayers.Layer.Vector(data.bridge_name);

    if (lastpoint != null) {
        var markerLayer = getPOI(lastpoint);
        vesselLayer.addFeatures([pointmap,markerLayer]);
    } else {
        vesselLayer.addFeatures([new OpenLayers.Feature.Vector(pointmap)]);
    }

// Function for creating a marker and returning it to the caller. 

function getPOI(point) {

//This was also tried without the "Style" property. (Only the externalGraphic line)
var temp_feature = new OpenLayers.Feature.Vector(
        point,
        style: { externalGraphic: '/assets/img/marker.png', graphicHeight: 16,     graphicWidth: 16, graphicXOffset:8, graphicYOffset:8  }
    );    

return temp_feature;
}

推荐答案

乍看之下，temp_feature定义有误:

At first glance, there's error in temp_feature definition:

var temp_feature = new OpenLayers.Feature.Vector(
    point,
    null,
    {
        externalGraphic: '/assets/img/marker.png',
        graphicHeight: 16,
        graphicWidth: 16,
        graphicXOffset:8,
        graphicYOffset:8
    }
); 

阅读并遵循API文档非常有用: http://dev.openlayers.org/docs/files/OpenLayers/Feature/Vector-js.html#OpenLayers.Feature.Vector.OpenLayers.Feature.Vector

It's useful to read and follow API documentation: http://dev.openlayers.org/docs/files/OpenLayers/Feature/Vector-js.html#OpenLayers.Feature.Vector.OpenLayers.Feature.Vector

OpenLayers.Feature.Vector接受三个参数，即几何图形，具有属性的对象(在您的情况下为null，因为您没有任何属性)和具有样式的对象.

OpenLayers.Feature.Vector takes three arguments, geometry, object with attributes (which is null in your case, since you don't have any attributes), and object with style.

我还没有测试过该代码，可能还会有其他问题.

I haven't tested that code, there may be other problems, too.

关于JavaScript的一般用法，从来没有这样的东西

And about general use of JavaScript, there is never such thing as

style: { externalGraphic: '/assets/img/marker.png', graphicHeight: 16,     graphicWidth: 16, graphicXOffset:8, graphicYOffset:8  }

对象总是在方括号内定义:

Object is always defined within brackets:

{style: { externalGraphic: '/assets/img/marker.png', graphicHeight: 16,     graphicWidth: 16, graphicXOffset:8, graphicYOffset:8  }}

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