Magnetometer sensor works only on a few devices

Question

I created an app just to test the tilt of the device’s X, Y and Z axes. In tests, some devices the sensors read the values, while others do not. I noticed that the TYPE_ACCELEROMETER sensor works on almost all the most current devices, but the TYPE_MAGNETIC_FIELD sensor does not work at all. Actually the TYPE_MAGNETIC_FIELD sensor does not exist on some phones or I should use another more current sensor that does the same function?

Below the Mainactivity code:

package br.com.exesensor_2019101;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements SensorEventListener {

    private SensorManager sensorManager;
    private Sensor accelerometer;
    private Sensor magnetometer;

    private float[] accelerometerReading = new float[3];
    private float[] magnetometerReading = new float[3];

    private float[] rotationMatrix = new float[9];
    private float[] remapCoordinate = new float[9];
    private float[] orientationAngles = new float[3];

    private TextView textViewX;
    private TextView textViewY;
    private TextView textViewZ;

    private static final int TAXA_LEITURA = 250000;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);

        textViewX = (TextView) findViewById(R.id.textViewX);
        textViewY = (TextView) findViewById(R.id.textViewY);
        textViewZ = (TextView) findViewById(R.id.textViewZ);

    }

    @Override
    protected void onResume() {
        super.onResume();
        accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        magnetometer = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);

        if (accelerometer == null || magnetometer == null){
            Toast.makeText(this, "Não foi possível acessar algum sensor do dispositivo!", Toast.LENGTH_SHORT).show();
            finish();
        }else {
            if (accelerometer != null) {
                sensorManager.registerListener(this, accelerometer, TAXA_LEITURA);
            }

            if (magnetometer != null) {
                sensorManager.registerListener(this, magnetometer, TAXA_LEITURA);
            }
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        sensorManager.unregisterListener(this);
    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        switch (event.sensor.getType()){
            case Sensor.TYPE_ACCELEROMETER:
                accelerometerReading = event.values.clone();
                break;
            case Sensor.TYPE_MAGNETIC_FIELD:
                magnetometerReading = event.values.clone();
                break;
        }
        updateOrientationAngles();
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int i) {

    }

    public void updateOrientationAngles() {
        if (accelerometerReading != null && magnetometerReading != null){
            SensorManager.getRotationMatrix(rotationMatrix, null, accelerometerReading, magnetometerReading);
            SensorManager.remapCoordinateSystem(rotationMatrix, SensorManager.AXIS_X, SensorManager.AXIS_Z, remapCoordinate);
            SensorManager.getOrientation(remapCoordinate, orientationAngles);

            textViewX.setText((String.format("Eixo X: %.2f°", orientationAngles[0] * 57.2957795f * -1)));
            textViewY.setText((String.format("Eixo Y: %.2f°", orientationAngles[1] * 57.2957795f * -1)));
            textViewZ.setText((String.format("Eixo Z: %.2f°", orientationAngles[2] * 57.2957795f * -1)));

            accelerometerReading = null;
            magnetometerReading = null;
        }
    }
}

Below the code of the XML Manifesto

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="br.com.exesensor_2019101">

    <uses-feature android:name="android.hardware.sensor.accelerometer" android:required="true" />
    <uses-feature android:name="android.hardware.sensor.compass" android:required="true"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Answer 1

Magnetometer is the sensor that gives the cell phone compass properties (Compass, in English). Not all phones have, and those that do not have an equivalent sensor.

For more information about sensors, see the Android documentation: https://developer.android.com/guide/topics/sensors/sensors_overview