我使用谷歌地方自动完成的地方建议。现在这就是我想要的：当用户键入不在谷歌数据库中的位置时，即谷歌返回零结果，我需要能够捕获零结果的事件，并激活我的自定义自动完成。
当谷歌返回零结果时如何找到？如果结果为零，则autocomplete.getPlace（）将返回状态，但这是在place_changed事件中，仅当用户从下拉列表中选择建议时才会触发该事件。如何在place_changed事件之外使其工作？
这是我使用的代码，请基于此提出建议：
autocomplete = new google.maps.places.Autocomplete(input,options);
google.maps.event.addListener(autocomplete, 'place_changed', function() {
var place = autocomplete.getPlace();
document.getElementById('place_name').value = place.name;
document.getElementById('location_lat').value = place.geometry.location.lat();
document.getElementById('location_lon').value = place.geometry.location.lng();
document.getElementById('location_add').value = place.formatted_address;
$('#locationInput').attr('title', place.formatted_address);
});
发现一招，
AutoComplete由输入节点的keyup事件触发，然后：
如果没有结果，请隐藏display: none;的结果下拉列表
要么
如果有结果，请通过清除display样式显示结果下拉列表
您可以通过document.getElementsByClassName('pac-container')[0]（本机）或$('.pac-container')（jQuery）获取下拉列表
因此，只需将下拉列表的display设置为“阻止”，然后跟踪它以检测结果状态。
从google official sample修改的简单示例：
<!DOCTYPE html>
<html>
<head>
<title>Google Maps JavaScript API v3 Example: Places Autocomplete</title>
<script src="https://maps.googleapis.com/maps/api/js?sensor=false&libraries=places"
type="text/javascript"></script>
<style type="text/css">
body {
font-family: sans-serif;
font-size: 14px;
}
#map_canvas {
height: 400px;
width: 600px;
margin-top: 0.6em;
}
</style>
<script type="text/javascript">
var ns = {}; // a name space
ns.checktimes = 0; // a couter of check times
// the check function
// @param dropdown: the drop-down list of Places.AutoComplete
// @param msg: the div to show message
ns._doCheck = function (dropdown, msg) {
if (dropdown.style.display == '') {
msg.innerHTML = 'has results? true';
ns.checkTimer = null;
}
else if (dropdown.style.display == 'none') {
msg.innerHTML = 'has results? false';
ns.checkTimer = null;
} else if (ns.checktimes < 20) { // check at most 10 seconds
ns.checktimes++;
ns.checkTimer = setTimeout(function () {
ns._doCheck(dropdown, msg);
}, 500);
}
}
function initialize() {
var mapOptions = {
center: new google.maps.LatLng(-33.8688, 151.2195),
zoom: 13,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
var map = new google.maps.Map(document.getElementById('map_canvas'),
mapOptions);
var input = document.getElementById('searchTextField');
var autocomplete = new google.maps.places.Autocomplete(input);
autocomplete.bindTo('bounds', map);
var infowindow = new google.maps.InfoWindow();
var marker = new google.maps.Marker({
map: map
});
google.maps.event.addListener(autocomplete, 'place_changed', function() {
infowindow.close();
var place = autocomplete.getPlace();
if (place.geometry.viewport) {
map.fitBounds(place.geometry.viewport);
} else {
map.setCenter(place.geometry.location);
map.setZoom(17); // Why 17? Because it looks good.
}
var image = new google.maps.MarkerImage(
place.icon,
new google.maps.Size(71, 71),
new google.maps.Point(0, 0),
new google.maps.Point(17, 34),
new google.maps.Size(35, 35));
marker.setIcon(image);
marker.setPosition(place.geometry.location);
var address = '';
if (place.address_components) {
address = [(place.address_components[0] &&
place.address_components[0].short_name || ''),
(place.address_components[1] &&
place.address_components[1].short_name || ''),
(place.address_components[2] &&
place.address_components[2].short_name || '')
].join(' ');
}
infowindow.setContent('<div><strong>' + place.name + '</strong><br>' + address);
infowindow.open(map, marker);
// update stored value
ns.oldValue = document.getElementById('searchTextField').value;
});
// Sets a listener on a radio button to change the filter type on Places
// Autocomplete.
function setupClickListener(id, types) {
var radioButton = document.getElementById(id);
google.maps.event.addDomListener(radioButton, 'click', function() {
autocomplete.setTypes(types);
});
}
setupClickListener('changetype-all', []);
setupClickListener('changetype-establishment', ['establishment']);
setupClickListener('changetype-geocode', ['geocode']);
}
// to check whether responsee and has results
function startCheck () {
// the input node
var inp = document.getElementById('searchTextField'),
value = inp.value; // value of input node
if (value && ns.oldValue != value) { // has value and changed, start check
// drop-down list and message div
var dropdown = document.getElementsByClassName('pac-container')[0],
msg = document.getElementById('msg');
// trick! change style to display='block'
dropdown.style.display = 'block';
// update stored value
ns.oldValue = value;
// initiate checktimes
ns.checktimes = 0;
// clear previous timer if exists
if (ns.checkTimer)
clearTimeout (ns.checkTimer);
ns.checkTimer = setTimeout(function () {
ns._doCheck(dropdown, msg);
}, 500);
}
}
google.maps.event.addDomListener(window, 'load', initialize);
</script>
</head>
<body>
<div>
<div id="msg">has results? </div>
<input id="searchTextField" type="text" size="50" onkeyup="startCheck();">
<input type="radio" name="type" id="changetype-all" checked="checked">
<label for="changetype-all">All</label>
<input type="radio" name="type" id="changetype-establishment">
<label for="changetype-establishment">Establishments</label>
<input type="radio" name="type" id="changetype-geocode">
<label for="changetype-geocode">Geocodes</lable>
</div>
<div id="map_canvas"></div>
</body>
</html>
我认为您的方案可能与Google返回零结果不同。您的问题中的一个假设是，place_changed事件“仅在用户从下拉列表中选择建议时才会被触发”，这是不正确的。来自google.maps.places.Autocomplete类place_changed的事件文档：
当PlaceResult可用于用户选择的地方时，将触发此事件。如果用户输入控件未建议的Place的名称并按Enter键，将触发place_changed事件，该事件包含name属性中的用户输入，未定义其他属性。
否则，Google应该返回结果，因为用户已选择自动填充下拉选项中的一个结果。如果直接用户输入不是驱动您的方案的原因，那么检查零结果不应仅仅涉及检查google.maps.places.PlaceResult属性的一个，一些或一部分，例如：
address_components google.maps.GeocoderAddressComponents数组idnamereferencetypes字符串数组（例如，[political，locality]或[restaurant，establishment]）您也可以通过这种方式获得结果。预测是谷歌地图返回的数组。
const displaySuggestions = (predictions, status) => {
if (status !== google.maps.places.PlacesServiceStatus.OK) {
if (status === 'ZERO_RESULTS') {
alert('zero results found')
}
return;
}
};
// you can create autocompleteService as variable outside the function as well
const autocompleteService = new google.maps.places.AutocompleteService();
// input is string of what user types
autocompleteService.getPlacePredictions({ input: input, types: ['address'] }, displaySuggestions);