OpenLayers 3根据属性选择并高亮feature

Posted 2020-10-05 marost

OpenLayers 3 版本：OpenLayers v4.3.2

想通过属性查询feature，但是在ol3中并没有发现类似ol2中的getFeatureByAttribute()....

自己写函数实现，实现方法如下：

var layer = new ol.layer.Vector({
        source: new ol.source.Vector({
            features:ol.Feature,
            url: ‘./resources/data/test.geojson‘,
            format: new ol.format.GeoJSON()
        }),
        style:polygonStyle
    });
    map.addLayer(layer);

function selectByAttribute(){
    var features = layer.getSource().getFeatures();
    //console.log(features);
    var value = ‘115街坊‘;
    var property = ‘name‘;
    var selectedByAttriFeature;//实际应用中设置成全局变量
    for (var i = 0, ii = features.length; i < ii; i++) {
        if (features[i].get(property) === value) {
            selectedByAttriFeature = features[i];
            break;
        }
    }
    selectedByAttriFeature.setStyle(featureSelectStyle);//高亮查询到的feature
    //console.log(selectedByAttriFeature.getGeometry().A);//后台输出发现，geometry属性中有一个属性A其实是中心点坐标，但是没有提供获取中心点的方法，.getGeometry().A也可获得中心点
    //console.log(getCenterOfExtent(selectedByAttriFeature.getGeometry().getExtent()));//结果同上

    var my_view = new ol.View({
        center: getCenterOfExtent(selectedByAttriFeature.getGeometry().getExtent()),
        zoom: 14
    });
    map.setView(my_view);
}

获得feature的中心点坐标：

function getCenterOfExtent(Extent){
    var X = Extent[0] + (Extent[2]-Extent[0])/2;
    var Y = Extent[1] + (Extent[3]-Extent[1])/2;
    return [X, Y];
}

清除已经选择的高亮feature：

function clearSelectByAttribute(){
    if(selectedByAttriFeature != null){
        selectedByAttriFeature.setStyle(null);
        selectedByAttriFeature = null;
    }
}