In general, the question is: pick the Studio to make an application that will show the angle of rotation of the device, below are two codes. In the first case, a gyroscope is used. I turn the smartphone - I get the angle to which I turned it. But there is a very big error, if I may say so. If you turn the phone very slowly, the angle will not be counted at all. In the second case, an accelerometer and a magnetic field are used. And he thinks very accurately - it does not matter if I turn the smartphone quickly or not. As for the first case, everything is extremely simple from the point of view of the code (although I don’t understand why I think so crookedly), and I can’t figure it out in the second code. I have already read everything on the line several times, but I still cannot understand this interaction. Can someone chew or direct where to go to study info. Can be foreign

Code snippet with a gyroscope

public class MainActivity extends AppCompatActivity implements SensorEventListener { private float rotateY = 0f; private SensorManager sensorManager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE); } @Override protected void onResume() { super.onResume(); sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE), SensorManager.SENSOR_DELAY_GAME); } @Override protected void onPause() { super.onPause(); sensorManager.unregisterListener(this); } @Override public void onSensorChanged(SensorEvent event) { float degree = Math.round(event.values[1]); rotateY += degree; Log.d("TAG", "rotateY: " + rotateY); } @Override public void onAccuracyChanged(Sensor sensor, int accuracy) { } }

Code snippet with accelerometer and magnetic field

 public class MainActivity extends Activity { TextView tvText; SensorManager sensorManager; Sensor sensorAccel; Sensor sensorMagnet; StringBuilder sb = new StringBuilder(); Timer timer; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); tvText = (TextView) findViewById(R.id.tvText); sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE); sensorAccel = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); sensorMagnet = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD); } @Override protected void onResume() { super.onResume(); sensorManager.registerListener(listener, sensorAccel, SensorManager.SENSOR_DELAY_NORMAL); sensorManager.registerListener(listener, sensorMagnet, SensorManager.SENSOR_DELAY_NORMAL); timer = new Timer(); TimerTask task = new TimerTask() { @Override public void run() { runOnUiThread(new Runnable() { @Override public void run() { getDeviceOrientation(); showInfo(); } }); } }; timer.schedule(task, 0, 10); } @Override protected void onPause() { super.onPause(); sensorManager.unregisterListener(listener); timer.cancel(); } String format(float values[]) { return String.format("%1$.1f\t\t%2$.1f\t\t%3$.1f", values[0], values[1], values[2]); } void showInfo() { sb.setLength(0); sb.append("Orientation : " + format(valuesResult)); tvText.setText(sb); } float[] r = new float[9]; void getDeviceOrientation() { SensorManager.getRotationMatrix(r, null, valuesAccel, valuesMagnet); SensorManager.getOrientation(r, valuesResult); valuesResult[0] = (float) Math.toDegrees(valuesResult[0]); valuesResult[1] = (float) Math.toDegrees(valuesResult[1]); valuesResult[2] = (float) Math.toDegrees(valuesResult[2]); return; } float[] valuesAccel = new float[3]; float[] valuesMagnet = new float[3]; float[] valuesResult = new float[3]; SensorEventListener listener = new SensorEventListener() { @Override public void onAccuracyChanged(Sensor sensor, int accuracy) { } @Override public void onSensorChanged(SensorEvent event) { switch (event.sensor.getType()) { case Sensor.TYPE_ACCELEROMETER: for (int i=0; i < 3; i++){ valuesAccel[i] = event.values[i]; } break; case Sensor.TYPE_MAGNETIC_FIELD: for (int i=0; i < 3; i++){ valuesMagnet[i] = event.values[i]; } break; } } };

}

The second code was taken from this article.

    1 answer 1

    Found the chemistry of this relationship here . Paragraph getRotationMatrix . And the code with the gyroscope works so crookedly, because this is the rotation speed in rad / c, I did not catch it right away