创建可拖动点

创建用户可以拖动的GeoJSON点;

<!DOCTYPE html>
<html lang="en">
<head>
    <title>创建可拖动点</title>
    <meta property="og:description" content="创建用户可以拖动的GeoJSON点" />
    <meta charset='utf-8'>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel='stylesheet' href='https://unpkg.com/maplibre-gl@5.5.0/dist/maplibre-gl.css' />
    <script src='https://unpkg.com/maplibre-gl@5.5.0/dist/maplibre-gl.js'></script>
    <style>
        body { margin: 0; padding: 0; }
        html, body, #map { height: 100%; }
    </style>
</head>
<body>
<div id="map"></div>
<script>
    const map = new maplibregl.Map({
        container: 'map',
        style:
            'https://api.maptiler.com/maps/streets/style.json?key=get_your_own_OpIi9ZULNHzrESv6T2vL',
        center: [0, 0],
        zoom: 2
    });

    const canvas = map.getCanvasContainer();

    const geojson = {
        'type': 'FeatureCollection',
        'features': [
            {
                'type': 'Feature',
                'geometry': {
                    'type': 'Point',
                    'coordinates': [0, 0]
                }
            }
        ]
    };

    function onMove(e) {
        const coords = e.lngLat;

        // 设置UI指示器
        canvas.style.cursor = 'grabbing';

        // 更新GeoJSON数据
        geojson.features[0].geometry.coordinates = [coords.lng, coords.lat];

        // 更新源
        map.getSource('point').setData(geojson);
    }

    function onUp(e) {
        const coords = e.lngLat;

        // 打印经纬度坐标
        console.log(`Longitude: ${coords.lng} Latitude: ${coords.lat}`);

        canvas.style.cursor = '';

        // 解绑移动事件
        map.off('mousemove', onMove);
        map.off('touchmove', onMove);
    }

    function onDown() {
        canvas.style.cursor = 'grab';

        map.on('mousemove', onMove);
        map.on('touchmove', onMove);

        map.once('mouseup', onUp);
        map.once('touchend', onUp);
    }

    map.on('load', () => {
        // 添加GeoJSON源
        map.addSource('point', {
            'type': 'geojson',
            'data': geojson
        });

        // 添加点图层
        map.addLayer({
            'id': 'point',
            'type': 'circle',
            'source': 'point',
            'paint': {
                'circle-radius': 10,
                'circle-color': '#F84C4C' // 红色
            }
        });

        // 当点击圆圈时进行交互
        map.on('mouseenter', 'point', () => {
            canvas.style.cursor = 'move';
        });

        map.on('mouseleave', 'point', () => {
            canvas.style.cursor = '';
        });

        map.on('mousedown', 'point', (e) => {
            // 防止地图拖动
            e.preventDefault();

            canvas.style.cursor = 'grab';

            map.on('mousemove', onMove);
            map.once('mouseup', onUp);
        });

        map.on('touchstart', 'point', (e) => {
            if (e.points.length !== 1) return;

            // 防止地图拖动
            e.preventDefault();

            map.on('touchmove', onMove);
            map.once('touchend', onUp);
        });
    });
</script>
</body>
</html>