Android开发获取重力加速度和磁场强度的方法

Sensor.getRotationMatrix (float[] R, float[] I, float[] gravity, float[] geomagnetic)

public class MainActivity extends AppCompatActivity implements SensorEventListener {
private static final String TAG = "CompassActivity";
private SensorManager sensorManager;
//记录rotationMatrix矩阵值
private float[] r = new float[9];
private float[] gravity = null;
private float[] geomagnetic = null;
private float[] I=new float[9];
private Handler handler=new Handler(){
@Override
public void handleMessage(Message msg) {
if(gravity!=null&&geomagnetic!=null)
{
if(SensorManager.getRotationMatrix(r, I, gravity, geomagnetic)) {
float gri = gravity[0] * r[6] + gravity[1] * r[7] + gravity[2] * r[8];
float h= (I[3]*r[0]+I[4]*r[3]+I[5]*r[6])*geomagnetic[0]+
(I[3]*r[1]+I[4]*r[4]+I[5]*r[7])*geomagnetic[1]+
(I[3]*r[2]+I[4]*r[5]+I[5]*r[8])*geomagnetic[2];
TextView textView = (TextView) findViewById(R.id.textView);
textView.setText("重力加速度" + gri + "n"+"磁场强度" + h + "n");
}
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onSensorChanged(SensorEvent sensorEvent) {
switch (sensorEvent.sensor.getType()){
case Sensor.TYPE_ACCELEROMETER:
gravity=sensorEvent.values;
handler.sendEmptyMessage(0);
break;
case Sensor.TYPE_MAGNETIC_FIELD:
geomagnetic=sensorEvent.values;
handler.sendEmptyMessage(0);
break;
default:break;
}
}
@Override
public void onAccuracyChanged(Sensor sensor, int i) {
}
private void showMessage(String message){
View view=findViewById(R.id.fab);
final Snackbar snackbar=Snackbar.make(view, message, Snackbar.LENGTH_INDEFINITE);
snackbar.setAction("关闭", new View.OnClickListener() {
@Override
public void onClick(View view) {
snackbar.dismiss();
}
});
snackbar.show();
}
@Override
protected void onPause() {
super.onPause();
sensorManager.unregisterListener(this);
}
@Override
protected void onResume() {
super.onResume();
Sensor sensor1=sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
sensorManager.registerListener(this,sensor1,SensorManager.SENSOR_DELAY_UI);
Sensor sensor2=sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
sensorManager.registerListener(this,sensor2,SensorManager.SENSOR_DELAY_UI);
}
}