TYPE_MAGNETIC_FIELD事件沒有在我的Galaxy Nexus上觸發ICS 4.0.2

Question

我試圖獲得手機的傾斜角度，並且我的這項活動在我的LG Optimus S上完美工作運行ICS 4.0.2的Verizon Galaxy Nexus的TYPE_MAGNETIC_FIELD事件永遠不會觸發。

因爲TYPE_MAGNETIC_FIELD事件永遠不會觸發，所以我沒有將mGravs數組傳遞到SensorManager.getRotationMatrix中。所以我不能說出手機的角度。就像我剛纔提到的，這段代碼在我的其他設備上效果很好，我可以看到電話的傾斜角度沒有問題。

任何知道爲什麼我不會用我的Galaxy Nexus獲得此事件？是否有任何對SDK的更改會阻止其發揮作用？

這裏是我的活動：

package com.rain.united; 

import android.app.Activity; 
import android.content.pm.ActivityInfo; 
import android.hardware.Sensor; 
import android.hardware.SensorEvent; 
import android.hardware.SensorEventListener; 
import android.hardware.SensorManager; 
import android.os.Bundle; 
import android.util.Log; 
import android.widget.TextView; 

public class Gameplay extends Activity implements SensorEventListener{ 
    private static final String TAG = "CameraDemo"; 
    private TextView mOrientationData; 
    private SensorManager mSensMan; 
    private float mAzimuth; 
    private float[] mGravs = new float[3]; 
    private float[] mGeoMags = new float[3]; 
    private float[] mOrientation = new float[3]; 
    private float[] mRotationM = new float[9]; 
    private float[] mRemapedRotationM = new float[9]; 
    private boolean mFailed; 

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

     mOrientationData = (TextView) findViewById(R.id.orientation_data); 

     mSensMan = (SensorManager) getSystemService(SENSOR_SERVICE); 
    } 

    protected void onResume() { 
     super.onResume(); 
     mSensMan.registerListener(this, mSensMan.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD), 
       SensorManager.SENSOR_DELAY_UI); 
     mSensMan.registerListener(this, mSensMan.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), 
       SensorManager.SENSOR_DELAY_UI); 
    } 

    protected void onPause() { 
     super.onPause(); 
     mSensMan.unregisterListener(this); 
    } 

    @Override 
    public void onAccuracyChanged(Sensor arg0, int arg1) { 
     // TODO Auto-generated method stub 

    } 

    @Override 
    public void onSensorChanged(SensorEvent event) { 
     if (event.accuracy == SensorManager.SENSOR_STATUS_UNRELIABLE) 
      return; 
     Log.d("united", "anything"); 
     switch (event.sensor.getType()) { 
      case Sensor.TYPE_MAGNETIC_FIELD: 
       //I NEVER GET TO THIS CODE ON MY GALAXY NEXUS 
       System.arraycopy(event.values, 0, mGravs, 0, 3); 
       Log.d("united", mGravs.toString()); 
       break; 
      case Sensor.TYPE_ACCELEROMETER: 
       // Here let's try another way: 
       for (int i=0;i<3;i++) mGeoMags[i] = event.values[i]; 
        break; 
       default: 
        return; 
     } 
     if (SensorManager.getRotationMatrix(mRotationM, null, mGravs, mGeoMags)){ 
      //Rotate to the camera's line of view (Y axis along the camera's axis) 
      //TODO: Find how to use android.opengl.Matrix to rotate to an arbitrary coordinate system. 
      SensorManager.remapCoordinateSystem(mRotationM, SensorManager.AXIS_X, 
        SensorManager.AXIS_Z, mRemapedRotationM); 
      SensorManager.getOrientation(mRemapedRotationM, mOrientation); 
      onSuccess(); 
     } else { 
      onFailure(); 
     } 
    } 

    void onSuccess(){ 
     if (mFailed) mFailed = false; 
     //  Convert the azimuth to degrees in 0.5 degree resolution. 
     mAzimuth = (float) Math.round((Math.toDegrees(mOrientation[0])) *2)/ 2; 
     //  Adjust the range: 0 < range <= 360 (from: -180 < range <= 180). 
     mAzimuth = (mAzimuth+360)%360; // alternative: mAzimuth = mAzimuth>=0 ? mAzimuth : mAzimuth+360; 
     mOrientationData.setText("Azimuth= " + mAzimuth); 
    } 
    void onFailure() { 
     if (!mFailed) { 
      mFailed = true; 
      mOrientationData.setText("didn't get rotation info"); 
     } 
    } 
} 

Answer 1

if (event.accuracy == SensorManager.SENSOR_STATUS_UNRELIABLE) return; 

刪除此行。磁性傳感器正在返回此準確性狀態，您的代碼正在丟棄這些事件。