如何在Google Map中添加缩放控件

Question

我想在我的谷歌地图的右下角显示放大（+）和缩小选项（ - ）。我尝试了这个，但我没有得到缩放选项。

 <script async defer
            src="https://maps.googleapis.com/maps/api/js?key=AIzaSyDQ2&callback=initMap">
    </script>
  <script type="text/javascript">
        window.onload = function () {
            var mapOptions = {
                center: new google.maps.LatLng(17.44633567526379, 78.38290556613924),
                zoom: 14,
                mapTypeId: google.maps.MapTypeId.ROADMAP
            };
            var infoWindow = new google.maps.InfoWindow();
            var latlngbounds = new google.maps.LatLngBounds();
            var map = new google.maps.Map(document.getElementById("dvMap"), mapOptions);
            google.maps.event.addListener(map, 'click', function (e) {
                alert("Latitude: " + e.latLng.lat() + "\r\nLongitude: " + e.latLng.lng());
                document.getElementById("txtLongitude").value = e.latLng.lng();
                document.getElementById("txtLatitude").value = e.latLng.lat();
            });
        }
    </script>
    <div id="dvMap" style="width: 700px; height: 300px">
    </div>

Answer 1

在MapOptions中添加zoomControl: true，如下所示：

var mapOptions = {
                center: new google.maps.LatLng(17.44633567526379, 78.38290556613924),
                zoomControl: true,
                zoom: 14,
                mapTypeId: google.maps.MapTypeId.ROADMAP
            };