How to clear leaflet map in reactjs by button?

问题

I want to clear my leaflet map by clicking a button...how to do this... I want to clear all drawed shapes on the map, so the map to be clear

This is my code of the leaflet map in the return statement:

 <Map
            key={this.state.keyMAP}
            style={{ height: "50vh" }}
            center={position}
            zoom={13}
            onClick={this.handleClick}
            onCreate={this.onCreate}
            onLocationfound={this.handleLocationFound}
          >
            {/* startDirectly */}

            <TileLayer
              attribution='&copy; <a href="http://osm.org/copyright">OpenStreetMap</a> contributors'
              url="http://{s}.tile.osm.org/{z}/{x}/{y}.png"
              layers="NDVI"
              // baseUrl="https://services.sentinel-hub.com/ogc/wms/bb1c8a2f-5b11-42bb-8ce4-dbf7f5300663"
            />

            <FeatureGroup>
              {viewMap && (
                <EditControl
                  position="topleft"
                  onEdited={this._onEditPath}
                  onCreated={this.onCreate}
                  onDeleted={this._onDeleted}
                  onMounted={this._mounted}
                  onEditStart={this._onEditStart}
                  onEditStop={this._onEditStop}
                  onDeleteStart={this._onDeleteStart}
                  onDeleteStop={this._onDeleteStop}
                  draw={{
                    rectangle: false,
                    marker: false,
                    circleMarker: false,
                    circle: false,
                    circlemarker: false,
                  }}
                />
              )}
            </FeatureGroup>
          </Map>

Button:

 <button
            className="waves-effect waves-light btn"
            onClick={this.resetMap}
          >
            Clear map
          </button>

Clear method:

resetMap() {
    console.log("Reset");
  }

Full code of my component:

https://github.com/SoilViews/SoilViews/blob/master/src/components/dashboard/Dashboard.js

回答1:

I will propose two solutions so that you can choose whichever suits you best. You just need to create DOM references of your map/feature group in React(depends on the chosen method). How to create a reference:

On your constructor, insert the following line:

 this.mapRef = React.createRef(); // Create a Map reference

OR

 this.fgRef = React.createRef(); // Create a Feature group reference

Then at your <Map> or <FeatureGroup> components you should add the following attributes accordingly:

<Map ref={this.mapRef} key={this.state.keyMAP} ....rest of the code

OR

<FeatureGroup ref={this.fgRef}> {viewMap && ( ....rest of the code

1. If you choose the map clearing method, you can proceed like this:

   function clearMap() {
     const map = this.mapRef.current.leafletElement;
     map.eachLayer(function (layer) {
       map.removeLayer(layer);
     });
   }
   

2. Or, if you choose the Feature Group method:

   function clearFeatureGroup() {
       const fg = this.fgRef.current.leafletElement;
       fg.clearLayers();
    }
   

Finally, in your button you can call the according method:

<button onClick={clearMap}>
   Clear!
</button>

OR

<button onClick={clearFeatureGroup}>
   Clear!
</button>

来源：https://stackoverflow.com/questions/62166577/how-to-clear-leaflet-map-in-reactjs-by-button