Android 手机方向概述（包括指南针）

Android

Android 手机方向概述（包括指南针）

Java
import Android.app.Activity;
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;
public class CompassActivity extends Activity implements SensorEventListener {
    private SensorManager sensorManager;
    private Sensor accelerometer;
    private Sensor magnetometer;
    private float[] lastAccelerometer = new float[3];
    private float[] lastMagnetometer = new float[3];
    private boolean lastAccelerometerSet = false;
    private boolean lastMagnetometerSet = false;
    private float[] rotationMatrix = new float[9];
    private float[] orientation = new float[3];
    private TextView compassTextView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setcontentView(R.layout.activity_compass);
        compassTextView = findViewById(R.id.compassTextView);
        sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        magnetometer = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
    }
    @Override
    protected void onResume() {
        super.onResume();
        sensorManager.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, magnetometer, SensorManager.SENSOR_DELAY_NORMAL);
    }
    @Override
    protected void onPause() {
        super.onPause();
        sensorManager.unregisterListener(this);
    }
    @Override
    public void onSensorChanged(SensorEvent event) {
        if (event.sensor == accelerometer) {
            System.arraycopy(event.values, 0, lastAccelerometer, 0, event.values.length);
            lastAccelerometerSet = true;
        } else if (event.sensor == magnetometer) {
            System.arraycopy(event.values, 0, lastMagnetometer, 0, event.values.length);
            lastMagnetometerSet = true;
        }
        if (lastAccelerometerSet && lastMagnetometerSet) {
            SensorManager.getRotationMatrix(rotationMatrix, null, lastAccelerometer, lastMagnetometer);
            SensorManager.getOrientation(rotationMatrix, orientation);
            float azimuthInRadians = orientation[0];
            float azimuthInDegrees = (float) Math.toDegrees(azimuthInRadians);
            compassTextView.setText("指南针方向：" + azimuthInDegrees);
        }
    }
    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        // 不需要处理精度变化的情况
    }
}

Android手机的方向传感器主要用于检测手机的方位和姿态变化，它包括地磁传感器和加速度传感器等。指南针应用通过这些传感器的数据来计算手机的方向，并在屏幕上显示出来。