OpenLayers Vector Layer最大功能数

Question

我想知道是否可以限制你在vectorylayer上绘制的功能数量。如果我已经绘制了多边形，然后去绘制另一个多边形，它将删除第一个特征。

如果没有，是否可以向矢量图层添加一个监听器，以便在点击绘图时可以删除所有功能？

感谢!!!

Answer 1

您无法在矢量图层上设置最大数量的功能，但它有很多事件可以注入您自己的逻辑。以下是可用的活动：

"beforefeatureadded", "beforefeaturesadded",
"featureadded", "featuresadded", "beforefeatureremoved",
"beforefeaturesremoved", "featureremoved", "featuresremoved",
"beforefeatureselected", "featureselected", "featureunselected", 
"beforefeaturemodified", "featuremodified", "afterfeaturemodified",
"vertexmodified", "vertexremoved", "sketchstarted",
"sketchmodified", "sketchcomplete", "refresh"

例如，您可以使用“beforefeatureadded”：

your_vectror_layer.events.on({'beforefeatureadded': function(){
  //Remove first feature or whatever you want to do
}});

Answer 2

你可以创建一个按钮，当你点击它时，它将删除你的矢量图层中的所有功能：

  

map.layers [1] .removeAllFeatures（）;

这里1是我的图层的id（我的矢量图层是OSM图层之后的第二个图标）

祝你好运！