Using the Google Maps API V3 from Delphi

The Google Maps Javascript API Version 2 has been officially deprecated, so it’s time to update to the new version 3, this post shows how you can use the new Google maps V3 API from Delphi.
in this sample application you can use the traffic layer , Bicycling layer and the street View Control to activate the panorama view.
for additional info about the Google maps api v3 you can check these links.

• Google Maps JavaScript API V3
• The Google Maps Javascript API V3 – Basics
• Google Map Javascript API V3 – Map Types

Check the next full commented sample application written in Delphi 2007, the source code is available in this location

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001	unit fMain;

002

003

interface

004

005

uses

006	Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

007	Dialogs, OleCtrls, SHDocVw, StdCtrls, ExtCtrls, XPMan, ComCtrls,MSHTML;

008

009

type

010	TfrmMain = class(TForm)

011	WebBrowser1: TWebBrowser;

012	LabelAddress: TLabel;

013	PanelHeader: TPanel;

014	ButtonGotoLocation: TButton;

015	XPManifest1: TXPManifest;

016	MemoAddress: TMemo;

017	ButtonGotoAddress: TButton;

018	LabelLatitude: TLabel;

019	LabelLongitude: TLabel;

020	Longitude: TEdit;

021	Latitude: TEdit;

022	CheckBoxTraffic: TCheckBox;

023	CheckBoxBicycling: TCheckBox;

024	CheckBoxStreeView: TCheckBox;

025	procedure FormCreate(Sender: TObject);

026	procedure ButtonGotoAddressClick(Sender: TObject);

027	procedure ButtonGotoLocationClick(Sender: TObject);

028	procedure CheckBoxTrafficClick(Sender: TObject);

029	procedure CheckBoxBicyclingClick(Sender: TObject);

030	procedure CheckBoxStreeViewClick(Sender: TObject);

031

private

032	{ Private declarations }

033	HTMLWindow2: IHTMLWindow2;

034

public

035	{ Public declarations }

036

end;

037

038

var

039	frmMain: TfrmMain;

040

041	implementation

042

043

uses

044

ActiveX;

045

046	{$R *.dfm}

047

048

const

049	HTMLStr: String = //i put The code for the web page page wich load the google maps in a string const, you can use an external html file too or embed the page in a resource and then load in a stream

050

' '+

051

' '+

052

' '+

053

' '+

054

' '+

118

''+

119

' '+

120

'  '+

121

''+

122

'';

123

124	procedure TfrmMain.FormCreate(Sender: TObject);

125

var

126	aStream     : TMemoryStream;

127

begin

128	WebBrowser1.Navigate('about:blank'); //Set the location to an empty page

129	if Assigned(WebBrowser1.Document) then

130

begin

131	aStream := TMemoryStream.Create; //create a TStem to load the Page from the string

132

try

133	aStream.WriteBuffer(Pointer(HTMLStr)^, Length(HTMLStr)); //Copy the string to the stream

134	//aStream.Write(HTMLStr[1], Length(HTMLStr));

135	aStream.Seek(0, soFromBeginning);

136	(WebBrowser1.Document as IPersistStreamInit).Load(TStreamAdapter.Create(aStream));//Load the page from the stream

137

finally

138	aStream.Free;

139

end;

140	HTMLWindow2 := (WebBrowser1.Document as IHTMLDocument2).parentWindow; //Set the instance of the parentWindow to call the javascripts functions

141

end;

142

end;

143

144	procedure TfrmMain.ButtonGotoLocationClick(Sender: TObject);

145

begin

146	HTMLWindow2.execScript(Format('GotoLatLng(%s,%s)',[Latitude.Text,Longitude.Text]), 'JavaScript');//Call the function GotoLatLng to go the coordinates

147

end;

148

149	procedure TfrmMain.ButtonGotoAddressClick(Sender: TObject);

150

var

151	address    : string;

152

begin

153	address := MemoAddress.Lines.Text;

154	address := StringReplace(StringReplace(Trim(address), #13, ' ', [rfReplaceAll]), #10, ' ', [rfReplaceAll]);

155	HTMLWindow2.execScript(Format('codeAddress(%s)',[QuotedStr(address)]), 'JavaScript');//Call the function codeAddress to go the address

156

end;

157

158	procedure TfrmMain.CheckBoxStreeViewClick(Sender: TObject);

159

begin

160	if CheckBoxStreeView.Checked then

161	HTMLWindow2.execScript('StreetViewOn()', 'JavaScript') //Activate the Street View option

162

else

163	HTMLWindow2.execScript('StreetViewOff()', 'JavaScript');//Deactivate the Street View option

164

165

end;

166

167	procedure TfrmMain.CheckBoxBicyclingClick(Sender: TObject);

168

begin

169	if CheckBoxBicycling.Checked then

170	HTMLWindow2.execScript('BicyclingOn()', 'JavaScript')//Activate the Bicycling View option

171

else

172	HTMLWindow2.execScript('BicyclingOff()', 'JavaScript');//Deactivate the Bicycling View option

173

end;

174

175	procedure TfrmMain.CheckBoxTrafficClick(Sender: TObject);

176

begin

177	if CheckBoxTraffic.Checked then

178	HTMLWindow2.execScript('TrafficOn()', 'JavaScript')//Activate the Traffic View option

179

else

180	HTMLWindow2.execScript('TrafficOff()', 'JavaScript');//Deactivate the Traffic View option

181

end;

182

183

end.

Source


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