在Openlayer3中仅允许一个绘图功能

Question

I'm using ol.interaction.Draw to draw points on my map. I would like to enable the user to draw one unique point each time he/she clicks on the "draw" icon. Any idea on how to do that?

Here is the code for the interaction:

function addInteraction() {
draw = new ol.interaction.Draw({
  source: sourceComments,
  type: "Point"
});

draw.on('drawend',
  function(evt) {
    // unset sketch
    sketch = null;
    var allFeatures = comments.getSource().getFeatures();
    var format = new ol.format.GeoJSON();
    document.getElementById('geometry').value =   JSON.stringify(format.writeFeatures(allFeatures), null, 4);
  }, this);

map.addInteraction(draw);
}

Thanks!

Answer 1

I had the same problem but used a different approach to solve it. I didn't use an interaction but caught the the click event in the map.

var pinpointFeature = new ol.Feature();         
var pinpointOverlay = new ol.FeatureOverlay({
    features: [pinpointFeature]
});         

map.on('click', function(event) {
    pinpointFeature.setGeometry(new ol.geom.Point(event.coordinate));
    //do something with your feature if needed
});

Answer 2

You could possibly remove the interaction from the map on the drawend event.

var draw;

function addInteraction() {
    draw = new ol.interaction.Draw({
        source: sourceComments,
        type: "Point"
    });

    draw.on('drawend', function(evt) {
        //... unset sketch
        map.removeInteraction(draw);
    }, this);

    map.addInteraction(draw);
}