如何从传单地图中删除标记

问题描述：

我在用户点击时在地图上添加标记。

问题是我只想要一个标记，但现在每当我点击地图时都会添加新标记。

I我试图删除它但没有任何反应：

I am adding marker on map on user click.
Problem is that I want only one marker but now whenever I click on map new marker is added.
I am trying to remove it but nothing happens:

var marker;
    map.on('click', function (e) {
        map.removeLayer(marker)

        marker = new L.Marker(e.latlng, { draggable: true });
        marker.bindPopup("<strong>" + e.latlng + "</strong>").addTo(map);

        marker.on('dragend', markerDrag);
    });

答

而不是使用 .on 要捕获和处理事件，您可以使用 .once 。这样，事件将只捕获一次，然后处理程序将解除绑定。

Instead of using .on to capture and handle the event, you could use .once. That way the event will be only captured once and the handler will unbind itself after that.

map.on('click', function () {
    console.log('I fire every click');
});

map.once('click', function () {
    console.log('I fire only once');
});

如果您需要自行取消绑定处理程序，可以使用。关。检查事件方法的参考： http://leafletjs.com/reference.html#events

If you're ever need to unbind a handler yourself you can use .off. Check the reference for event methods: http://leafletjs.com/reference.html#events

至于为什么上面的代码无法正常工作，首次点击时你会尝试删除标记： map.removeLayer（marker），但变量 marker 不包含L.Marker实例，因此地图无法删除它。您应该先检查它是否已经定义，然后将其删除：

As to why your code above isn't working, on first click you're trying remove the marker: map.removeLayer(marker), but the variable marker doesn't contain a L.Marker instance so the map is unable to remove it. You should check if it's defined first and only then remove it:

var marker;
map.on('click', function (e) {
    if (marker) { // check
        map.removeLayer(marker); // remove
    }
    marker = new L.Marker(e.latlng); // set
});

这是关于Plunker的一个工作示例： http://plnkr.co/edit/iEcivecU7HGajQqDWzVH?p=preview

Here's a working example on Plunker: http://plnkr.co/edit/iEcivecU7HGajQqDWzVH?p=preview

如何从传单地图中删除标记

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