Using my demo VCL Sensor listing application (a blog post from last year), I got the following list of sensors found on my Samsung Series 7 Slate:
Notice that GPSDirect Sensor appears in the list of sensors found for TSensorCategory.Location.
Delphi's System.Sensors unit includes definitions for the following categories of sensors (TSensorCategory):
For each sensor category the unit defines (currently) the following possible sensor types:
- TLocationSensorType = (GPS, Static, Lookup, Triangulation, Broadcast, DeadReckoning, Other);
- TEnvironmentalSensorType = (Temperature, AtmosphericPressure, Humidity, WindSpeed, WindDirection);
- TMotionSensorType = (Accelerometer1D, Accelerometer2D, Accelerometer3D, MotionDetector, Gyrometer1D, Gyrometer2D, Gyrometer3D, Speedometer);
- TOrientationSensorType = (Compass1D, Compass2D, Compass3D, Inclinometer1D, Inclinometer2D, Inclinometer3D, Distance1D, Distance2D, Distance3D);
- TElectricalSensorType = (Voltage, Current, Capacitance, Resistance, Inductance, ElectricalPower, Potentiometer);
- TMechanicalSensorType = (BooleanSwitch, BooleanSwitchArray, MultiValueSwitch, Force, Scale, Pressure, Strain);
- TBiometricSensorType = (HumanPresence, HumanProximity, Touch);
- TLightSensorType = (AmbientLight); (Note: I showed how to use the AmbientLight sensor in your VCL apps at http://blogs.embarcadero.com/davidi/2013/12/02/43032)
- TScannerSensorType = (RFID, Barcode);
To build a simple VCL location enabled application I start by creating a new VCL Delphi application project. I added a TButton and five TLabel components to my form. Three of the labels will contain a) text declaring that a location sensor was found or not found, b) the latitude and longitude of my current location if a location sensor is found. Here is what my form looks like:
For the Button OnClick event handler I added the following code to get the location sensor using the TSensorManager GetSensorsByCategory method. GetSensorsByCategory takes a TSensorCategory as a parameter and returns a TSensorArray as a result. Using the method's result I instantiate a TCustomLocationSensor and get the latitude and longitude floating point values. Finally the OnClick event code uses ShellExecute to open a window and display a Google Map using the location coordinates. Here is the code for my button event handler:
GoogleMapsURL: String = 'https://maps.google.com/maps?q=%s,%s&output=embed';
procedure TForm1.Button1Click(Sender: TObject);
MyLocationSensorArray : TSensorArray;
MyLocationSensor : TCustomLocationSensor;
TSensorManager.Current.Activate; // activate sensor manager
MyLocationSensorArray := TSensorManager.Current.GetSensorsByCategory(TSensorCategory.Location);
if MyLocationSensorArray <> nil then begin
Label3.Caption := 'Location Sensor Found';
MyLocationSensor := MyLocationSensorArray as TCustomLocationSensor;
LatitudeLabel.Caption := FloatToStr(MyLocationSensor.Latitude);
LongitudeLabel.Caption := FloatToStr(MyLocationSensor.Longitude);
Label3.Caption := 'Location Sensor Not Found!'
TSensorManager.Current.DeActivate // deactivate sensor manager
When compiled and run using Delphi XE5 on my Samsung Series 7 Slate (I also testing it on my Dell desktop at home and my Dell notebook at work), I get the following program displays here in our Scotts Valley office:
I also get a Windows notification that my application has used the location API. Here is a snapshot of my Windows Event Viewer:
Its simple to location enable your Windows apps using VCL. Of course it would be even easier when I have a TLocationSensor non-visual component that works with my VCL apps. Stay tuned for a future post, unless someone else beats me to it.
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