OpenLayers3基础教程——OL3之Popup

概述：

本节重点讲述OpenLayers3中Popup的调用时实现，OL3改用Overlay代替OL2的Popup功能。

接口简介：

overlay跟ol.control.Control一样，是一个可见的窗口，但是不和Control一样，不是固定在地图区域的某个部分，而是显示在一个地图坐标上，随着地图的移动或者缩放而移动的。其调用方式如下：

var popup = new ol.Overlay({  element: document.getElementById('popup')});popup.setPosition(coordinate);map.addOverlay(popup);

new ol.Overlay(options)

src/ol/overlay.js, line 69

NameTypeDescriptionoptions

Overlay options.

NameTypeDescriptionelementElement | undefined

The overlay element.

offsetArray.<number> |undefined

Offsets in pixels used when positioning the overlay. The fist element in the array is the horizontal offset. A positive value shifts the overlay right. The second element in the array is the vertical offset. A positive value shifts the overlay down. Default is [0, 0].

positionol.Coordinate |undefined

The overlay position in map projection.

positioningol.OverlayPositioning| string | undefined

Defines how the overlay is actually positioned with respect to its position property. Possible values are'bottom-left', 'bottom-center', 'bottom-right', 'center-left', 'center-center','center-right', 'top-left', 'top-center', and 'top-right'. Default is 'top-left'.

stopEventboolean | undefined

Whether event propagation to the map viewport should be stopped. Default is true. If true the overlay is placed in the same container as that of the controls (CSS class name ol-overlaycontainer-stopevent); iffalse it is placed in the container with CSS class name ol-overlaycontainer.

insertFirstboolean | undefined

Whether the overlay is inserted first in the overlay container, or appended. Default is true. If the overlay is placed in the same container as that of the controls (see the stopEvent option) you will probably setinsertFirst to true so the overlay is displayed below the controls.

Fires:

• change:element (ol.ObjectEvent)
• change:map (ol.ObjectEvent)
• change:offset (ol.ObjectEvent)
• change:position (ol.ObjectEvent)
• change:positioning (ol.ObjectEvent)

Extends

• ol.Object

Observable Properties

NameTypeSettableol.ObjectEvent typeDescriptionelementElement | undefinedyeschange:element

The Element containing the overlay.

mapol.Map | undefinedyeschange:map

The map that the overlay is part of.

offsetArray.<number>yeschange:offset

The offset.

positionol.Coordinate | undefinedyeschange:position

The spatial point that the overlay is anchored at.

positioningol.OverlayPositioningyeschange:positioning

How the overlay is positioned relative to its point on the map.

Methods

getElement(){Element|undefined}

src/ol/overlay.js, line 160

Get the DOM element of this overlay.

Returns:

The Element containing the overlay. 

getMap(){ol.Map|undefined}

src/ol/overlay.js, line 176

Get the map associated with this overlay.

Returns:

The map that the overlay is part of. 

getOffset(){Array.<number>}

src/ol/overlay.js, line 192

Get the offset of this overlay.

Returns:

The offset. 

getPosition(){ol.Coordinate|undefined}

src/ol/overlay.js, line 209

Get the current position of this overlay.

Returns:

The spatial point that the overlay is anchored at. 

getPositioning(){ol.OverlayPositioning}

src/ol/overlay.js, line 226

Get the current positioning of this overlay.

Returns:

How the overlay is positioned relative to its point on the map. 

on(type, listener, opt_this){goog.events.Key} inherited

src/ol/observable.js, line 65

Listen for a certain type of event.

NameTypeDescriptiontypestring | Array.<string>

The event type or array of event types.

listenerfunction

The listener function.

thisObject

The object to use as this in listener.

Returns:

Unique key for the listener. 

once(type, listener, opt_this){goog.events.Key} inherited

src/ol/observable.js, line 78

Listen once for a certain type of event.

NameTypeDescriptiontypestring | Array.<string>

The event type or array of event types.

listenerfunction

The listener function.

thisObject

The object to use as this in listener.

Returns:

Unique key for the listener. 

setElement(element)

src/ol/overlay.js, line 312

Set the DOM element to be associated with this overlay.

NameTypeDescriptionelementElement | undefined

The Element containing the overlay.

setMap(map)

src/ol/overlay.js, line 327

Set the map to be associated with this overlay.

NameTypeDescriptionmapol.Map | undefined

The map that the overlay is part of.

setOffset(offset)

src/ol/overlay.js, line 342

Set the offset for this overlay.

NameTypeDescriptionoffsetArray.<number>

Offset.

setPosition(position)

src/ol/overlay.js, line 358

Set the position for this overlay.

NameTypeDescriptionpositionol.Coordinate | undefined

The spatial point that the overlay is anchored at.

setPositioning(positioning)

src/ol/overlay.js, line 374

Set the positioning for this overlay.

NameTypeDescriptionpositioningol.OverlayPositioning

how the overlay is positioned relative to its point on the map.

un(type, listener, opt_this) inherited

src/ol/observable.js, line 91

Unlisten for a certain type of event.

NameTypeDescriptiontypestring | Array.<string>

The event type or array of event types.

listenerfunction

The listener function.

thisObject

The object which was used as this by the listener.

unByKey(key) inherited

src/ol/observable.js, line 101

Removes an event listener using the key returned by on() or once().

NameTypeDescriptionkeygoog.events.Key

Key.

上面的内容是OL3 的API中关于overlay的部分。

调用示例：

1、popup样式

body, #map {border: 0px;margin: 0px;padding: 0px;width: 100%;height: 100%;font-size: 13px;}.ol-popup {display: none;position: absolute;background-color: white;-moz-box-shadow: 0 1px 4px rgba(0,0,0,0.2);-webkit-filter: drop-shadow(0 1px 4px rgba(0,0,0,0.2));filter: drop-shadow(0 1px 4px rgba(0,0,0,0.2));border: 1px solid #cccccc;bottom: 12px;left: -50px;width: 200px;}.ol-popup:after, .ol-popup:before {top: 100%;border: solid transparent;content: " ";height: 0;width: 0;position: absolute;pointer-events: none;}.ol-popup:after {border-top-color: white;border-width: 10px;left: 48px;margin-left: -10px;}.ol-popup:before {border-top-color: #cccccc;border-width: 11px;left: 48px;margin-left: -11px;}.popup-title{font-weight: bold;border-bottom:1px solid #cccccc;padding: 5px 8px;}.popup-content{padding: 5px 8px;}.ol-popup-closer {text-decoration: none;position: absolute;top: 6px;right: 6px;}.ol-popup-closer:after {content: "✖";}

2、popup容器

<div id="map"><div id="popup" class="ol-popup"><a href="#" id="popup-closer" class="ol-popup-closer"></a><div id="popup-title" class="popup-title"></div><div id="popup-content" class="popup-content"></div></div></div>

3、实现js

var container = document.getElementById('popup');var content = document.getElementById('popup-content');var title = document.getElementById('popup-title');var closer = document.getElementById('popup-closer');closer.onclick = function(){container.style.display = 'none';closer.blur();return false;};var overlay = new ol.Overlay({element: container});map.addOverlay(overlay);

map.on('click', function(evt) {var coordinate = evt.coordinate;var hdms = ol.coordinate.toStringHDMS(ol.proj.transform(coordinate, 'EPSG:4326', 'EPSG:4326'));overlay.setPosition(coordinate);content.innerHTML = '<p>You clicked here:</p><code>' + hdms +'</code>';container.style.display = 'block';title.innerHTML = "提示信息";title.style.display = 'block';map.getView().setCenter(coordinate);});

示例完整代码如下：

<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>Ol3 popup</title><link rel="stylesheet" type="text/css" href="http://localhost/ol3/css/ol.css"/><style type="text/css">body, #map {border: 0px;margin: 0px;padding: 0px;width: 100%;height: 100%;font-size: 13px;}.ol-popup {display: none;position: absolute;background-color: white;-moz-box-shadow: 0 1px 4px rgba(0,0,0,0.2);-webkit-filter: drop-shadow(0 1px 4px rgba(0,0,0,0.2));filter: drop-shadow(0 1px 4px rgba(0,0,0,0.2));border: 1px solid #cccccc;bottom: 12px;left: -50px;width: 200px;}.ol-popup:after, .ol-popup:before {top: 100%;border: solid transparent;content: " ";height: 0;width: 0;position: absolute;pointer-events: none;}.ol-popup:after {border-top-color: white;border-width: 10px;left: 48px;margin-left: -10px;}.ol-popup:before {border-top-color: #cccccc;border-width: 11px;left: 48px;margin-left: -11px;}.popup-title{font-weight: bold;border-bottom:1px solid #cccccc;padding: 5px 8px;}.popup-content{padding: 5px 8px;}.ol-popup-closer {text-decoration: none;position: absolute;top: 6px;right: 6px;}.ol-popup-closer:after {content: "✖";}</style><script type="text/javascript" src="http://localhost/ol3/build/ol.js"></script><script type="text/javascript" src="http://localhost/jquery/jquery-1.8.3.js"></script><script type="text/javascript">function init(){var format = 'image/png';var bounds = [73.4510046356223, 18.1632471876417,134.976797646506, 53.5319431522236];var untiled = new ol.layer.Image({source: new ol.source.ImageWMS({ratio: 1,url: 'http://localhost:8081/geoserver/lzugis/wms',params: {'FORMAT': format,'VERSION': '1.1.1',LAYERS: 'lzugis:capital',STYLES: ''}})});var projection = new ol.proj.Projection({code: 'EPSG:4326',units: 'degrees'});var container = document.getElementById('popup');var content = document.getElementById('popup-content');var title = document.getElementById('popup-title');var closer = document.getElementById('popup-closer');closer.onclick = function(){container.style.display = 'none';closer.blur();return false;};var overlay = new ol.Overlay({element: container});map.addOverlay(overlay);var map = new ol.Map({controls: ol.control.defaults({attribution: false}),target: 'map',layers: [untiled],overlays: [overlay],view: new ol.View({projection: projection})});map.getView().fitExtent(bounds, map.getSize());map.on('click', function(evt) {var coordinate = evt.coordinate;var hdms = ol.coordinate.toStringHDMS(ol.proj.transform(coordinate, 'EPSG:4326', 'EPSG:4326'));overlay.setPosition(coordinate);content.innerHTML = '<p>You clicked here:</p><code>' + hdms +'</code>';container.style.display = 'block';title.innerHTML = "提示信息";title.style.display = 'block';map.getView().setCenter(coordinate);});}</script></head><body onLoad="init()"><div id="map"><div id="popup" class="ol-popup"><a href="#" id="popup-closer" class="ol-popup-closer"></a><div id="popup-title" class="popup-title"></div><div id="popup-content" class="popup-content"></div></div></div></body></html>

实现后的效果如下：

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