多个Google Map 折线点击了活动

我使用谷歌 Map Api构建了一个网络应用程序，并解决了折线点击事件的问题 . 我试图在 Map 上添加一些标记，然后将它们连接在一起 . 我希望如果我点击折线，我可以获得该折线的起点和终点的标记 . 但是，我单击不同的折线时，只有一个结果返回相同的结果 . 这是我的源代码：

var locations = [
    { title: "Site 1", lat: 16.044137, lng: 108.206511 },
    { title: "Site 2", lat: 16.067161, lng: 108.186259 },
    { title: "Site 3", lat: 16.063472, lng: 108.215248 },
    { title: "Site 4", lat: 16.041847, lng: 108.193539 },
    { title: "Site 5", lat: 16.054186, lng: 108.172890 },
];

var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 14,
    center: new google.maps.LatLng(16.067161, 108.186259),
    mapTypeId: google.maps.MapTypeId.SATELLITE
});

var infowindow = new google.maps.InfoWindow();

var polyLineClicked = function (polyline, fromIndex, toIndex) {
    google.maps.event.addListener(polyline, 'click', function (e) {
        infowindow.setContent = fromIndex + " to " + toIndex;
        infowindow.setPosition = event.latLng;
        infowindow.open(map);
    });
}
for (var i = 0; i < locations.length; i++) {
    var position = new google.maps.LatLng(locations[i].lat, locations[i].lng);
   var marker = new google.maps.Marker({
        position: position,
        map: map
    });

    google.maps.event.addListener(marker, 'click', (function (marker, i) {
        return function () {
            infowindow.setContent(locations[i].title);
            infowindow.open(map, marker);
        }
    })(marker, i));

    if (i <= locations.length - 2) {

        var nextPosition = new google.maps.LatLng(locations[i + 1].lat, locations[i + 1].lng);
        var polyline = new google.maps.Polyline({
            path: [position, nextPosition],
            strokeColor: 'black',
            strokeOpacity: 1,
            strokeWeight: 7,
            map: map,
            fromPositionIndex: i,
            toPositionIndex: i+1
        });
        var fromIndex = locations[i].title;
        var toIndex = locations[i + 1].title;

        polyLineClicked(polyline, fromIndex, toIndex);
    }
}