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Xamarin.Essentials: Magnetometer

  • Artikkeli

The Magnetometer class lets you monitor the device's magnetometer sensor which indicates the device's orientation relative to Earth's magnetic field.

Get started

To start using this API, read the getting started guide for Xamarin.Essentials to ensure the library is properly installed and set up in your projects.

Using Magnetometer

Add a reference to Xamarin.Essentials in your class:

using Xamarin.Essentials;

The Magnetometer functionality works by calling the Start and Stop methods to listen for changes to the magnetometer. Any changes are sent back through the ReadingChanged event. Here is sample usage:


public class MagnetometerTest
{
    // Set speed delay for monitoring changes.
    SensorSpeed speed = SensorSpeed.UI;

    public MagnetometerTest()
    {
        // Register for reading changes.
        Magnetometer.ReadingChanged += Magnetometer_ReadingChanged;
    }

    void Magnetometer_ReadingChanged(object sender, MagnetometerChangedEventArgs e)
    {
        var data = e.Reading;
        // Process MagneticField X, Y, and Z
        Console.WriteLine($"Reading: X: {data.MagneticField.X}, Y: {data.MagneticField.Y}, Z: {data.MagneticField.Z}");
    }

    public void ToggleMagnetometer()
    {
        try
        {
            if (Magnetometer.IsMonitoring)
              Magnetometer.Stop();
            else
              Magnetometer.Start(speed);
        }
        catch (FeatureNotSupportedException fnsEx)
        {
            // Feature not supported on device
        }
        catch (Exception ex)
        {
            // Other error has occurred.
        }
    }
}

All data is returned in µT (microteslas).

Sensor Speed

  • Fastest – Get the sensor data as fast as possible (not guaranteed to return on UI thread).
  • Game – Rate suitable for games (not guaranteed to return on UI thread).
  • Default – Default rate suitable for screen orientation changes.
  • UI – Rate suitable for general user interface.

If your event handler is not guaranteed to run on the UI thread, and if the event handler needs to access user-interface elements, use the MainThread.BeginInvokeOnMainThread method to run that code on the UI thread.

API