LazDeviceAPIs

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This article applies to Android only.

See also: Multiplatform Programming Guide

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LazDeviceAPIs is a LCL unit which offers an interface to various hardware devices, such as the accelerometer, GPS positioning, SMS sending, etc. It is mostly designed for smartphone/mobile platforms, but it might eventually be ported to desktops too.

Introduction

LazDeviceAPIs was modeled to be similar to other APIs for hardware devices from the LCL. Historically we had two hardware global objects: Mouse and Screen, respectively for the pointing device (Mouse is also utilized for touch messages) and Screen for the display. In LazDeviceAPIs there are global objects: Accelerometer, PositionInfo, Messaging, etc.

Accelerometer

The Accelerometer is very easy to use. Just call Accelerometer.StartReadingAccelerometerData to start listening to the accelerometer sensor and call Accelerometer.StopReadingAccelerometerData to stop listening to it:

uses lazdeviceapis;
    
    procedure TForm2.btnStartAccelClick(Sender: TObject);
    begin
      Accelerometer.OnSensorChanged := @HandleAccelerometerChanged;
      Accelerometer.StartReadingAccelerometerData();
    end;
    
    procedure TForm2.btnStopAccelClick(Sender: TObject);
    begin
      Accelerometer.StopReadingAccelerometerData();
    end;
    
    procedure TForm2.HandleAccelerometerChanged(Sender: TObject);
    begin
      labelSensorData.Caption := Format('X=%f Y=%f Z=%f', [Accelerometer.xaxis,
        Accelerometer.yaxis, Accelerometer.zaxis]);
      DebugLn(labelSensorData.Caption);
    end;

Android Permissions

This object requires no special permissions under Android.

PositionInfo

Android Permissions

Using the PositionInfo global object in Android requires adding the following permissions to the AndroidManifest.xml file of the application, as can be seen below.

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

Messaging

Android Permissions

Using the Messaging global object in Android requires adding the following permissions to the AndroidManifest.xml file of the application, as can be seen below.

<uses-permission android:name="android.permission.SEND_SMS" />

Possible Windows implementation

Windows 7 and up has a sensors API that gives access to sensor info (e.g. GPS); see [1(http://msdn.microsoft.com/en-us/library/windows/desktop/dd318936%28v=vs.85%29.aspx)]. Interested developers may be able to use those APIs to provide LazDeviceAPIs functionality.

Roadmap

LazDeviceAPIs is currently implemented only for LCL-CustomDrawn-Android

See Also

• Custom Drawn Interface/Android
• Talk:LazDeviceAPIs

From the Free Pascal wiki, page "LazDeviceAPIs", as the Internet Archive kept it on 2024-09-20, last changed on 2020-02-19. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.