显示gsensor即时数据的apk && 用gsensor来判断手机的静和动

即时显示gsensor的数据，可以在调试重力感应器驱动和测试手机性能时起到很好的作用。类似的，SensorEventListener还可以用在其他感应器的场合，比如光感应、地磁感应。这里用两种方式来完成读取并显示gsensor数据的功能，一种是activity和SensorEventListener监听分离，在不同类中完成；另一种是在同一个activity中完成（*）。

（1）activity和SensorEventListener监听分离

        Acvitivity启动时初始化SensorEventListener，在退出activity时注销Listener。

import android.os.Bundle;
import android.app.Activity;

import android.util.Log;
import android.view.Menu;
import android.widget.TextView;

public class Activity01 extends Activity {
    private final String TAG = "zhangcheng";
    SensorListenerTest sensorListenerTest;        //sensor监听类，同一个包里的类被调用时不需要import
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activity01);
        sensorListenerTest = new SensorListenerTest(this);     //监听类的构造函数，activity通过this句柄跟监听类绑定
    }

    protected void onResume(){
        super.onResume();
        sensorListenerTest.enableSensor();          //activity启动后使能sensor监听
    }

    protected void onStop(){
        super.onStop();
        sensorListenerTest.disableSensor();                    //出于系统控制原因，在退出activity时注销监听
    }
}

      SensorListenerTest类，监听gsensor数据。注意import android.hardware.sensor的四个类。

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.util.Log;

public class SensorListenerTest implements SensorEventListener   {   //使用listsen的接口，所以必须实现接口的两个成员函数
    private final String TAG = "zhangcheng";
    private SensorManager mSensorManager;
    private Sensor sensor;
    private float mLastX,mLastY,mLastZ;    // X Y Z三轴数据
    private Context mContext;

    public SensorListenerTest(Context context){
        mContext = context;
    }

    public void enableSensor(){
        mSensorManager = (SensorManager)mContext.getSystemService(Context.SENSOR_SERVICE);   //获得系统的sensor服务
        sensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);     //具体要操作的sensor类型

        if(mSensorManager == null){
            Log.i(TAG,"sensor not supported");
        }
        mSensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_NORMAL);  //以普通采样率注册监听器
    }

    public void disableSensor(){
        if(mSensorManager != null){
            mSensorManager.unregisterListener(this);       //注销监听器
            mSensorManager = null;
        }
    }

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

    public void onSensorChanged(SensorEvent event){     //必须完成SensorEventListener的响应函数
        if(event.sensor == null){
            return;
        }

        if(event.sensor.getType() == Sensor.TYPE_ACCELEROMETER){
            mLastX = event.values[0];
            mLastY = event.values[1];
            mLastZ = event.values[2];        //得到XYZ三轴数据

            String sX = String.valueOf(mLastX);
            String sY = String.valueOf(mLastY);
            String sZ = String.valueOf(mLastZ);    //利用String的成员函数valueOf快速将float型转成String型

            Log.i(TAG,"mLastX == "+sX);
            Log.i(TAG,"mLastY == "+sY);
            Log.i(TAG,"mLastZ == "+sZ);       //在Logcat中即时提示读出的gsensor数据
        }
    }
}

       运行结果诸如在Logcat中显示：

01-02 23:28:41.634: I/zhangcheng(2238): mLastX == -0.181
01-02 23:28:41.634: I/zhangcheng(2238): mLastY == 0.143
01-02 23:28:41.634: I/zhangcheng(2238): mLastZ == 9.979
01-02 23:28:41.808: I/zhangcheng(2238): mLastX == -0.143
01-02 23:28:41.808: I/zhangcheng(2238): mLastY == 0.172
01-02 23:28:41.808: I/zhangcheng(2238): mLastZ == 10.008

（2）单一activity完成监听。上述方法完成后在Logcat中显示读数不太直观，可以直接在activity上用textview来显示。

import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.view.Menu;
import android.widget.TextView;

public class Activity01 extends Activity implements SensorEventListener{     //在继承activity类的同时使用listsen接口
    private final String TAG = "zhangcheng";
    private SensorManager mSensorManager;
    private Sensor sensor;
    private float mLastX,mLastY,mLastZ;
    private String sX,sY,sZ;

    private TextView mTextViewX = null;
    private TextView mTextViewY = null;
    private TextView mTextViewZ = null;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activity01);

        mTextViewX = (TextView)findViewById(R.id.TextView1);
        mTextViewY = (TextView)findViewById(R.id.TextView2);
        mTextViewZ = (TextView)findViewById(R.id.TextView3);    //绑定显示控件句柄

        mSensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
        sensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);

        if(mSensorManager == null){
            Log.i(TAG,"sensor not supported");
    }
    mSensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_NORMAL);
     }

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

    public void onSensorChanged(SensorEvent event){          //在activity中完成该接口函数
        if(event.sensor == null){
            return;
        }

        if(event.sensor.getType() == Sensor.TYPE_ACCELEROMETER){
            mLastX = event.values[0];
            mLastY = event.values[1];
            mLastZ = event.values[2];

            sX = String.valueOf(mLastX);
            sY = String.valueOf(mLastY);
            sZ = String.valueOf(mLastZ);

            mTextViewX.setText(sX);
            mTextViewY.setText(sY);
            mTextViewZ.setText(sZ);   //由于该接口函数不断刷新，所以可以把控件显示函数放在这里显示
        }
    }

    protected void onStop(){                          //同样在退出activity时要注销监听
        super.onStop();
        if(mSensorManager != null){
            mSensorManager.unregisterListener(this);
            mSensorManager = null;
        }
    }
}

       该函数可在一个activity中即时显示gsensor数据，方便查看。 

========================================================================================================================

        现实中的很多手机应用会到gsensor这个感应器，比如手机的倾斜角度，手机的运动方向和加速度。如果我们要在一个服务中通过监控gsensor的数据来判断手机的静止或者运动，进而作相应处理。流程是：原始数据 -> 低通滤波 -> 重力在3个方向的分量 -> 判断即可。以下步骤：

（1）服务定义时要implements SensorEventListener接口，以下是一些变量。

private SensorManager mSensorManager;          //sensor管理器
private Sensor sensor;
private float[] curGravity = new float[3];  //xyz重力数据
private lowPassFilter filter1;
private lowPassFilter filter2;
private firLowPassFilter firFilter1;
private firLowPassFilter firFilter2;
private firLowPassFilter firFilter3;        //低通滤波的一些类的内容
private int mAccSkipCnt = 0;        //抖动计数
private static final int __ACC_SKIP_SAMPLES = 30;   // 跳过刚开始的若干个加速度采样
private int _NTAPS = 6;
private double[] h = {
        0.125514644795420960,
        0.414388923238107440,
        -0.013420976983735622,
        -0.013420976983735622,
        0.414388923238107440,
        0.125514644795420960
        };
private boolean DeviceFlating = false;  //手机是否平躺了

（2）在服务onCreate函数中定义sensor相关变量，并设置低通滤波的一些系数

mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE);
sensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
mSensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_NORMAL);
filter1 = new lowPassFilter(1, 20);
filter2 = new lowPassFilter(0, 0.9f);
firFilter1 = new firLowPassFilter(_NTAPS, h);
firFilter2 = new firLowPassFilter(_NTAPS, h);
firFilter3 = new firLowPassFilter(_NTAPS, h);

（3）SensorEventListener接口中要完成的成员函数

public void onSensorChanged(SensorEvent event){
        if(event.sensor == null){
            return;
        }
        mIsSmartStayOn= Settings.System.getInt(cr,"isSmartStayEnabled",0) == 1 ? true : false;//人眼识别打开时才启动重力监听
        if(mIsSmartStayOn == true){
            Log.i(TAG,"gsensor respond");

            curGravity[0] = (float)firFilter1.filter1((double)event.values[0]);
            curGravity[1] = (float)firFilter2.filter1((double)event.values[1]);
            curGravity[2] = (float)firFilter3.filter1((double)event.values[2]);
            curGravity = filter1.SMAFilter(curGravity);     //取得三轴重力数据并滤波处理

            if(mAccSkipCnt < __ACC_SKIP_SAMPLES) {
                mAccSkipCnt++;
                return ;                    //待gsensor读数稳定才继续后面的处理
            }

            float[] linearAcc = new float[]{
                    event.values[0]-curGravity[0],
                    event.values[1]-curGravity[1],
                    event.values[2]-curGravity[2]
            };
            double linearLen = KonkaGeneHelper.vecLength(linearAcc);    //三轴数据平方和相加开根号的结果
            Log.w(TAG,"linearLen is "+linearLen);
            if(linearLen < 0.6f && DeviceFlating == false){  //如果手机一开始没有静止并且linearLen小于0.6
                DeviceFlating = true;           //手机趋近于静止状态（不论方向）
            }
            if(linearLen > 1.0f && DeviceFlating == true && pm.isScreenOn() == true){
                DisplayEyeIcon(1);          //如果手机静止的，并且gsensor检测到linearLen大于1且手机亮屏                 freshDetect();
                DeviceFlating = false;      //马上启动人眼识别
            }
        }
    }

通过以上过程，可以参考其中的重力计算和判断流程用在其他场合。

 

参考原文：http://www.cnblogs.com/snowdrop/articles/1802092.html