OpenLayers.Control.SelectFeature

在OpenLayers中，控件SelectFeature主要用於操作(鼠標移入、移出、單擊、雙擊)矢量圖層(OpenLayers.Layer.Vector)的要素。那么它是如何實現的呢，還是讓我們看代碼吧。

• 首先我們還是先把所有要用到類實例化出來，參考代碼：

var map=new OpenLayers.Map("map");
var vectorLayer = new OpenLayers.Layer.Vector();
map.addLayer(vectorLayer);

• 矢量要素的單擊事件，僅需在實例化類時注冊onSelect事件即可，參考代碼：

var sf=new OpenLayer.Control.SelectFeature(vectorLayer,{onSelect:function(currentFeature){//todo}});
map.addControl(sf);

• 矢量要素的鼠標移入事件，需要實例化時注冊onSelect事件，同時設置hover屬性為true，參考代碼：

var sf=new OpenLayer.Control.SelectFeature(vectorLayer,{onSelect:function(currentFeature){todo},hover:true});
map.addControl(sf);

• 矢量要素的鼠標各種事件的混合操作，如需要鼠標移入、移出、單擊、雙擊等事件，參考代碼：

var callbacks = {
    over:function(currentFeature){},
    out:function(currentFeature){},
    dblclick:function(currentFeature){}
};
var sf = new OpenLayers.Control.SelectFeature(vectorLayer,{
    onSelect:function(currentFeature){},
});
map.addControl(sf);

• 對於事件的混合操作行為，我們不能在callbacks對象中同時注冊click和dblclick事件，這樣的話單擊事件會屏蔽雙擊事件。對於下述代碼，dblclick事件永不觸發：

var callbacks = {
     over:function(currentFeature){},
     out:function(currentFeature){},
     click:function(currentFeature){},
     dblclick:function(currentFeature){}
};
var sf = new OpenLayers.Control.SelectFeature(vectorLayer,{
     onSelect:function(currentFeature){},
 });
map.addControl(sf);