檢測Android的方向(Orientation) - Azimuth, Pitch, Roll

前文談到如何使用SensorEventListener()檢測加速度計(Accelerometer)的數據. 本文使用同樣的方法, 檢測Android的方向(Orientation), 方位(Azimuth), 俯仰(Pitch)和橫滾(Roll).

簡單不過: 把sensorManager.getSensorList(Sensor.TYPE_ACCELEROMETER)修改為sensorManager.getSensorList(Sensor.TYPE_ORIENTATION)便成.

在SensorEventListener()的onSensorChanged事件傳回的是一個傳感器事件對象(SensorEvent), 其中SensorEvent.value[0], SensorEvent.value[1]和SensorEvent.value[2]就是Azimuth, Pitch和Roll值, 以度角(degree)為單位.
SensorEvent.value[0]：方位(Azimuth), 圍繞Z軸(0~359), Y軸和磁北之間的角度. 0=北，90=東，180=南，270=西.
SensorEvent.value[1]：俯仰(Pitch)，圍繞X軸(-180~180), Z軸向Y軸為正數.
SensorEvent.value[2]：橫滾(Roll)，圍繞Y軸(-90~90)，與正面的價值觀當 X軸向Z軸為正數.

因為Android Emulator沒有帶方向傳感器, 所以需要在真正的設備上運行.

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   >
<TextView 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="@string/hello"
   />
<TextView 
   android:id="@+id/info"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/textx"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="X: "
   />
<TextView 
   android:id="@+id/texty"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="Y: "
   />
<TextView 
   android:id="@+id/textz"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="Z: "
   />
</LinearLayout>

AndroidOrientationInfo.java

package com.AndroidOrientationInfo;

import java.util.List;

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;
import android.widget.Toast;

public class AndroidOrientationInfo extends Activity {
 
 SensorManager sensorManager;
 boolean accelerometerPresent;
 Sensor accelerometerSensor;
 
 TextView textInfo, textX, textY, textZ;
 
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
      
       textInfo = (TextView)findViewById(R.id.info);
       textX = (TextView)findViewById(R.id.textx);
       textY = (TextView)findViewById(R.id.texty);
       textZ = (TextView)findViewById(R.id.textz);
      
       sensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE); 
       List<Sensor> sensorList = sensorManager.getSensorList(Sensor.TYPE_ORIENTATION);
      
       if(sensorList.size() > 0){
        accelerometerPresent = true;
        accelerometerSensor = sensorList.get(0);
        
        String strSensor  = "Name: " + accelerometerSensor.getName()
         + "\nVersion: " + String.valueOf(accelerometerSensor.getVersion()) 
         + "\nVendor: " + accelerometerSensor.getVendor() 
         + "\nType: " + String.valueOf(accelerometerSensor.getType()) 
         + "\nMax: " + String.valueOf(accelerometerSensor.getMaximumRange()) 
         + "\nResolution: " + String.valueOf(accelerometerSensor.getResolution()) 
         + "\nPower: " + String.valueOf(accelerometerSensor.getPower()) 
         + "\nClass: " + accelerometerSensor.getClass().toString();
        textInfo.setText(strSensor);
       }
       else{
        accelerometerPresent = false;
       }
      
   }

 @Override
 protected void onResume() {
  // TODO Auto-generated method stub
  super.onResume();
  
  if(accelerometerPresent){
   sensorManager.registerListener(accelerometerListener, accelerometerSensor, SensorManager.SENSOR_DELAY_NORMAL);
   Toast.makeText(this, "Register accelerometerListener", Toast.LENGTH_LONG).show();
  }
 }
 
 @Override
 protected void onStop() {
  // TODO Auto-generated method stub
  super.onStop();
  
  if(accelerometerPresent){
   sensorManager.unregisterListener(accelerometerListener);
   Toast.makeText(this, "Unregister accelerometerListener", Toast.LENGTH_LONG).show();
  }
 }

 private SensorEventListener accelerometerListener = new SensorEventListener(){

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

  @Override
  public void onSensorChanged(SensorEvent event) {
   // TODO Auto-generated method stub
   textX.setText("X: " + String.valueOf(event.values[0]));
   textY.setText("Y: " + String.valueOf(event.values[1]));
   textZ.setText("Z: " + String.valueOf(event.values[2]));
  }};
}