Question

我试图让矢量的方向指向相机，相对于磁北。我的印象是我需要使用getOrientation（）返回的值，但我不确定它们代表什么。当我改变手机的方向时，我从getOrientation（）获得的值不会发生可预测的变化（旋转90度不会将值改变90度）。我需要知道getOrientation（）返回的值是什么意思。到目前为止我所写的内容如下：

package com.example.orientation;

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.Toast;

public class Orientation extends Activity{

 private SensorManager mSM;
 private mSensorEventListener mSEL;

    float[] inR = new float[16];
    float[] outR= new float[16];
    float[] I = new float[16];
    float[] gravity = new float[3];
    float[] geomag = new float[3];
    float[] orientVals = new float[3];

    final float pi = (float) Math.PI;
    final float rad2deg = 180/pi;    

 /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mSM = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        mSEL = new mSensorEventListener();  

        mSM.registerListener(mSEL, 
       mSM.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),
       SensorManager.SENSOR_DELAY_NORMAL);

     mSM.registerListener(mSEL, 
       mSM.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD), 
       SensorManager.SENSOR_DELAY_NORMAL);

 }



 private class mSensorEventListener implements SensorEventListener{

  @Override
  public void onAccuracyChanged(Sensor arg0, int arg1) {}

  @Override
  public void onSensorChanged(SensorEvent event) {

   // If the sensor data is unreliable return
   if (event.accuracy == SensorManager.SENSOR_STATUS_UNRELIABLE)
    return;

   // Gets the value of the sensor that has been changed
   switch (event.sensor.getType()){  
   case Sensor.TYPE_ACCELEROMETER:
    gravity = event.values.clone();
    break;
   case Sensor.TYPE_MAGNETIC_FIELD:
    geomag = event.values.clone();
    break;
   }

   // If gravity and geomag have values then find rotation matrix
   if (gravity != null && geomag != null){

    // checks that the rotation matrix is found
    boolean success = SensorManager.getRotationMatrix(inR, I, gravity, geomag);
    if (success){

     // Re-map coordinates so y-axis comes out of camera
     SensorManager.remapCoordinateSystem(inR, SensorManager.AXIS_X, 
       SensorManager.AXIS_Z, outR);

     // Finds the Azimuth and Pitch angles of the y-axis with 
     // magnetic north and the horizon respectively
     SensorManager.getOrientation(outR, orientVals);
     float azimuth = orientVals[0]*rad2deg;
     float pitch = orientVals[1]*rad2deg;
     float roll = orientVals[2]*rad2deg;

     // Displays a pop up message with the azimuth and inclination angles
     String endl = System.getProperty("line.separator");
     Toast.makeText(getBaseContext(), 
       "Rotation:" +
       outR[0] + " " + outR[1] + " " + outR[2] + endl +
       outR[4] + " " + outR[5] + " " + outR[6] + endl +
       outR[8] + " " + outR[9] + " " + outR[10] + endl +endl +
       "Azimuth: " + azimuth + " degrees" + endl + 
       "Pitch: " + pitch + " degrees" + endl +
       "Roll: " + roll + " degrees", 
       Toast.LENGTH_LONG).show();
    } /*else
     Toast.makeText(getBaseContext(), 
       "Get Rotation Matrix Failed", Toast.LENGTH_LONG).show();*/
   }   
  }

    }

}

我查看了有关sensorManager类的文档，但它没有帮助解决这个问题。如果有人能帮助我从中获得意义，我会非常感激。我正在测试运行Android 2.1的Nexus One

Answer 1

因为我是android的新手，所以我使用toast在屏幕上显示信息。我把它更改为只更新视图上的文本，这似乎解决了它。我也发现我认为orientVals实际上是正确的。我需要的是不使用滚筒。还没有意识到有一种方法可以从rad转换为deg内置，所以我只是使用它。

Answer 2

您可以查看屏幕上显示原始值的logger application。在其描述中，您将找到源代码的链接，以便您可以了解它如何访问传感器。

HTH，丹尼尔

Answer 3

您需要获取设备的方向（横向/纵向）并做出一些补偿。

SensorManager.getOrientation(R, values);  
mHeading = (int) Math.toDegrees(values[0]); 
Display display = 
((WindowManager)getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
int compensation = display.getRotation() * 90;                          
mHeading = mHeading+compensation;

Answer 4

我认为你应该使用getInclination来获取方向而不是获取方向。因为getRotationMatrix是基于重力和地磁场进行计算的，你将直接从磁场中获得定位。

Answer 5

我认为你应该在行getOrientation

中将outR更改为inR

boolean success = SensorManager.getRotationMatrix(inR, I, gravity, geomag);
if (success){
 // Re-map coordinates so y-axis comes out of camera
 SensorManager.remapCoordinateSystem(inR, SensorManager.AXIS_X, 
   SensorManager.AXIS_Z, outR);

 // Finds the Azimuth and Pitch angles of the y-axis with 
 // magnetic north and the horizon respectively
 **SensorManager.getOrientation(inR, orientVals);**

使用getRotationMatrix（）和getOrientation（）查找方向

5 个答案: