【发布时间】：2016-05-13 18:15:19
【问题描述】：
我正在将地址传递给 Google 地图，并且能够在 TWebBrowser 中显示地图并放置标记，但我还试图将纬度和经度坐标返回到我的 Delphi Win32 应用程序。我需要添加什么？
private
{ Private declarations }
HTMLWindow2: IHTMLWindow2;
fAddress: String;
public
{ Public declarations }
constructor create(AOwner: TComponent; AAddress: string); reintroduce;
end;
var
ViewMaps : TViewMaps;
Flags : OLEVariant;
address, MapType : string;
Title, Lat, Lng : AnsiString;
implementation
Uses ShredMain, ActiveX, MaintForm_u, NewSchedule;
{$R *.dfm}
constructor TViewMaps.create(AOwner: TComponent; AAddress: string);
begin
inherited create(AOwner);
fAddress := AAddress; // fAddress is now stored to form variable
end;
const
HTMLStr: AnsiString =
'<html> '+
'<head> '+
'<meta name="viewport" content="initial-scale=1.0, user-scalable=yes" /> '+
//'<meta http-equiv="X-UA-Compatible" content="IE=edge" />'+
'<input type="hidden" id="lat" value="" />'+
'<input type="hidden" id="lng" value="" />'+
''+
'<script type="text/javascript" src="http://maps.google.com/maps/api/js?v=3.22"></script> '+
'<script type="text/javascript"> '+
''+
''+
' var geocoder; '+
' var map; '+
' var trafficLayer;'+
' var bikeLayer;'+
' var markersArray = [];'+
''+
''+
' function initialize() { '+
' geocoder = new google.maps.Geocoder();'+
' var latlng = new google.maps.LatLng(40.714776,-74.019213); '+
' var myOptions = { '+
' zoom: 11, '+
' center: latlng, '+
' mapTypeId: google.maps.MapTypeId.ROADMAP '+
' }; '+
' map = new google.maps.Map(document.getElementById("map_canvas"), myOptions); '+
' trafficLayer = new google.maps.TrafficLayer();'+
' bikeLayer = new google.maps.BicyclingLayer();'+
' map.set("streetViewControl", false);'+
' } '+
''+
''+
' function codeAddress(address) { '+
' if (geocoder) {'+
' geocoder.geocode( { address: address}, function(results, status) { '+
' if (status == google.maps.GeocoderStatus.OK) {'+
' map.setCenter(results[0].geometry.location);'+
' PutMarker(results[0].geometry.location.lat(), results[0].geometry.location.lng(), results[0].geometry.location.lat()+","+results[0].geometry.location.lng());'+
' document.getElementById("lat").value = results[0].geometry.location.lat;'+
' document.getElementById("lng").value = results[0].geometry.location.lng;'+
' } else {'+
' alert("Geocode was not successful for the following reason: " + status);'+
' }'+
' });'+
' }'+
' }'+
''+
''+
' function GotoLatLng(Lat, Lang) { '+
' var latlng = new google.maps.LatLng(Lat,Lang);'+
' map.setCenter(latlng);'+
' PutMarker(Lat, Lang, Lat+","+Lang);'+
' }'+
''+
''+
'function ClearMarkers() { '+
' if (markersArray) { '+
' for (i in markersArray) { '+
' markersArray[i].setMap(null); '+
' } '+
' } '+
'} '+
''+
' function PutMarker(Lat, Lang, Msg) { '+
' var latlng = new google.maps.LatLng(Lat,Lang);'+
' var marker = new google.maps.Marker({'+
' position: latlng, '+
' map: map,'+
' title: Msg+" ("+Lat+","+Lang+")"'+
' });'+
' markersArray.push(marker); '+
' }'+
''+
''+
' function TrafficOn() { trafficLayer.setMap(map); }'+
''+
' function TrafficOff() { trafficLayer.setMap(null); }'+
''+''+
' function BicyclingOn() { bikeLayer.setMap(map); }'+
''+
' function BicyclingOff(){ bikeLayer.setMap(null);}'+
''+
' function StreetViewOn() { map.set("streetViewControl", true); }'+
''+
' function StreetViewOff() { map.set("streetViewControl", false); }'+
''+
''+'</script> '+
'</head> '+
'<body onload="initialize()"> '+
' <div id="map_canvas" style="width:100%; height:100%"></div> '+
'</body> '+
'</html> ';
procedure TViewMaps.OnShow(Sender: TObject);
var
aStream: TMemoryStream;
HtmlElement: IHtmlElement;
sLat, sLng: string;
begin
WebBrowser1.Navigate('about:blank');
MemoAddress.Lines.Text := NewServiceForm.MapAddress;
if Assigned(WebBrowser1.Document) then
begin
aStream := TMemoryStream.Create;
try
aStream.WriteBuffer(Pointer(HTMLStr)^, Length(HTMLStr));
aStream.Seek(0, soFromBeginning);
(WebBrowser1.Document as IPersistStreamInit).Load(TStreamAdapter.Create(aStream));
finally
aStream.Free;
end;
HTMLWindow2 := (WebBrowser1.Document as IHTMLDocument2).parentWindow;
end;
while WebBrowser1.ReadyState <> READYSTATE_COMPLETE do // wait for google
begin
sleep(0);
application.processmessages;
end;
// 05/11/2016 - Show the address on the map
fAddress := StringReplace(StringReplace(Trim(fAddress), #13, ' ', [rfReplaceAll]), #10, ' ', [rfReplaceAll]);
HTMLWindow2.execScript(Format('codeAddress(%s)',[QuotedStr(fAddress)]), 'JavaScript');
HtmlElement := (WebBrowser1.document as IHTMLDocument3).getElementById('lat');
sLat := HtmlElement.getAttribute('value', 0);
HtmlElement := (WebBrowser1.document as IHTMLDocument3).getElementById('lng');
sLng := HtmlElement.getAttribute('value', 0);
LatitudeEdit.Text := sLat;
LongitudeEdit.Text := sLng;
end;
我将 Lat 和 Lng 定义为 AnsiString，但 sLat 和 sLng 在我的 OnShow 事件中本地定义为 String。我的两个经度和纬度 Tedit 框是空白的。我是否将错误的变量传递给他们？
【问题讨论】：
-
@John Easley - 为了让它工作，我必须在geometry.location.lat 的末尾添加 ()，但只有当我添加像 ShowMessage('Hello ') 在我的 OnShow 事件中的 HtmlElement := 之后。否则结果为空。为什么？
标签： javascript google-maps delphi