顯示gsensor即時數據的apk && 用gsensor來判斷手機的靜和動

即時顯示gsensor的數據，可以在調試重力感應器驅動和測試手機性能時起到很好的作用。類似的，SensorEventListener還可以用在其他感應器的場合，比如光感應、地磁感應。這裏用兩種方式來完成讀取並顯示gsensor數據的功能，一種是activity和SensorEventListener監聽分離，在不同類中完成；另一種是在同一個activity中完成（*）。

（1）activity和SensorEventListener監聽分離

        Acvitivity啓動時初始化SensorEventListener，在退出activity時註銷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監聽類，同一個包裏的類被調用時不需要import
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activity01);
        sensorListenerTest = new SensorListenerTest(this);     //監聽類的構造函數，activity通過this句柄跟監聽類綁定
    }

    protected void onResume(){
        super.onResume();
        sensorListenerTest.enableSensor();          //activity啓動後使能sensor監聽
    }

    protected void onStop(){
        super.onStop();
        sensorListenerTest.disableSensor();                    //出於系統控制原因，在退出activity時註銷監聽
    }
}

      SensorListenerTest類，監聽gsensor數據。注意import android.hardware.sensor的四個類。

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，所以必須實現接口的兩個成員函數
    private final String TAG = "zhangcheng";
    private SensorManager mSensorManager;
    private Sensor sensor;
    private float mLastX,mLastY,mLastZ;    // X Y Z三軸數據
    private Context mContext;

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

    public void enableSensor(){
        mSensorManager = (SensorManager)mContext.getSystemService(Context.SENSOR_SERVICE);   //獲得系統的sensor服務
        sensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);     //具體要操作的sensor類型

        if(mSensorManager == null){
            Log.i(TAG,"sensor not supported");
        }
        mSensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_NORMAL);  //以普通採樣率註冊監聽器
    }

    public void disableSensor(){
        if(mSensorManager != null){
            mSensorManager.unregisterListener(this);       //註銷監聽器
            mSensorManager = null;
        }
    }

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

    public void onSensorChanged(SensorEvent event){     //必須完成SensorEventListener的響應函數
        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三軸數據

            String sX = String.valueOf(mLastX);
            String sY = String.valueOf(mLastY);
            String sZ = String.valueOf(mLastZ);    //利用String的成員函數valueOf快速將float型轉成String型

            Log.i(TAG,"mLastX == "+sX);
            Log.i(TAG,"mLastY == "+sY);
            Log.i(TAG,"mLastZ == "+sZ);       //在Logcat中即時提示讀出的gsensor數據
        }
    }
}

       運行結果諸如在Logcat中顯示：

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）單一activity完成監聽。上述方法完成後在Logcat中顯示讀數不太直觀，可以直接在activity上用textview來顯示。

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{     //在繼承activity類的同時使用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);    //綁定顯示控件句柄

        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中完成該接口函數
        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);   //由於該接口函數不斷刷新，所以可以把控件顯示函數放在這裏顯示
        }
    }

    protected void onStop(){                          //同樣在退出activity時要註銷監聽
        super.onStop();
        if(mSensorManager != null){
            mSensorManager.unregisterListener(this);
            mSensorManager = null;
        }
    }
}

       該函數可在一個activity中即時顯示gsensor數據，方便查看。 

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

        現實中的很多手機應用會到gsensor這個感應器，比如手機的傾斜角度，手機的運動方向和加速度。如果我們要在一個服務中通過監控gsensor的數據來判斷手機的靜止或者運動，進而作相應處理。流程是：原始數據 -> 低通濾波 -> 重力在3個方向的分量 -> 判斷即可。以下步驟：

（1）服務定義時要implements SensorEventListener接口，以下是一些變量。

private SensorManager mSensorManager;          //sensor管理器
private Sensor sensor;
private float[] curGravity = new float[3];  //xyz重力數據
private lowPassFilter filter1;
private lowPassFilter filter2;
private firLowPassFilter firFilter1;
private firLowPassFilter firFilter2;
private firLowPassFilter firFilter3;        //低通濾波的一些類的內容
private int mAccSkipCnt = 0;        //抖動計數
private static final int __ACC_SKIP_SAMPLES = 30;   // 跳過剛開始的若干個加速度採樣
private int _NTAPS = 6;
private double[] h = {
        0.125514644795420960,
        0.414388923238107440,
        -0.013420976983735622,
        -0.013420976983735622,
        0.414388923238107440,
        0.125514644795420960
        };
private boolean DeviceFlating = false;  //手機是否平躺了

（2）在服務onCreate函數中定義sensor相關變量，並設置低通濾波的一些係數

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接口中要完成的成員函數

public void onSensorChanged(SensorEvent event){
        if(event.sensor == null){
            return;
        }
        mIsSmartStayOn= Settings.System.getInt(cr,"isSmartStayEnabled",0) == 1 ? true : false;//人眼識別打開時才啓動重力監聽
        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);     //取得三軸重力數據並濾波處理

            if(mAccSkipCnt < __ACC_SKIP_SAMPLES) {
                mAccSkipCnt++;
                return ;                    //待gsensor讀數穩定才繼續後面的處理
            }

            float[] linearAcc = new float[]{
                    event.values[0]-curGravity[0],
                    event.values[1]-curGravity[1],
                    event.values[2]-curGravity[2]
            };
            double linearLen = KonkaGeneHelper.vecLength(linearAcc);    //三軸數據平方和相加開根號的結果
            Log.w(TAG,"linearLen is "+linearLen);
            if(linearLen < 0.6f && DeviceFlating == false){  //如果手機一開始沒有靜止並且linearLen小於0.6
                DeviceFlating = true;           //手機趨近於靜止狀態（不論方向）
            }
            if(linearLen > 1.0f && DeviceFlating == true && pm.isScreenOn() == true){
                DisplayEyeIcon(1);          //如果手機靜止的，並且gsensor檢測到linearLen大於1且手機亮屏                 freshDetect();
                DeviceFlating = false;      //馬上啓動人眼識別
            }
        }
    }

通過以上過程，可以參考其中的重力計算和判斷流程用在其他場合。

 

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