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Android开发获取重力加速度和磁场强度的方法

2020-02-21 17:22:57
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大多数Android手机都有传感器,它包括很多功能,这里就不一一诉说了,今天武林技术频道小编为大家带来的是Android开发获取重力加速度和磁场强度的方法,希望能帮到您。

Android获取重力加速度和磁场强度主要依靠:

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

输入数据:

gravity为重力传感器测得的重力加速度float[3];
geomagnetic为罗盘传感器测得的地磁数据float[3];

输出数据:

R为通过这个方法计算得到的从手机的设备到坐标系到真实世界坐标系的转换矩阵

I为从将地磁数据转换到重力数据所在坐标的旋转矩阵

[0 0 g] = R * gravity (g = 重力加速度)
[0 m 0] = I * R * geomagnetic (m = 磁场强度)

下面是我做的结果图

核心部分代码如下:

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);  }}希望武林技术频道小编介绍的Android开发获取重力加速度和磁场强度的方法,能让你有所感悟,武林技术频道会为大家继续推荐更多专业知识。
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