显示gsensor即时数据的apk && 用gsensor来判断手机的静和动 &&气压计的测试应用

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。

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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。

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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。

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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。

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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

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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

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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。

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测试气压计的应用如下：

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public class MainActivity extends Activity {

private SensorManager mSensorManager=null;

private Sensor mSensor=null;

private TextView textView1=null;

private Button button1=null;

private Button button2=null;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

textView1=(TextView)findViewById(R.id.textView1);

/*获取系统服务（SENSOR_SERVICE）返回一个SensorManager对象*/

mSensorManager=(SensorManager)getSystemService(SENSOR_SERVICE);

/*通过SensorManager获取相应的（压力传感器）Sensor类型对象*/

mSensor=mSensorManager.getDefaultSensor(Sensor.TYPE_PRESSURE);

/*注册相应的SensorService*/

button1=(Button)findViewById(R.id.button1);

button1.setOnClickListener(new Button.OnClickListener() {

@Override

public void onClick(View arg0) {

mSensorManager.registerListener(mSensorEventListener, mSensor

, SensorManager.SENSOR_DELAY_NORMAL);

}

});

/* 销毁相应的SensorService

* 很关键的部分，注意，说明文档中提到，即使Activity不可见的时候，感应器依然会继续工作

* 所以一定要关闭触发器，否则将消耗用户大量电量*/

button2=(Button)findViewById(R.id.button2);

button2.setOnClickListener(new Button.OnClickListener() {

@Override

public void onClick(View v) {

mSensorManager.unregisterListener(mSensorEventListener, mSensor);

}

});

}

/*声明一个SensorEventListener对象用于侦听Sensor事件，并重载onSensorChanged方法*/

private final SensorEventListener mSensorEventListener=new SensorEventListener() {

@Override

public void onSensorChanged(SensorEvent event) {

if(event.sensor.getType()==Sensor.TYPE_PRESSURE){

/*压力传感器返回当前的压强，单位是百帕斯卡hectopascal（hPa）。*/

float pressure=event.values[0];

textView1.setText(String.valueOf(pressure)+"hPa");

}

}

@Override

public void onAccuracyChanged(Sensor sensor, int accuracy) {

// TODO Auto-generated method stub

}

};

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// Inflate the menu; this adds items to the action bar if it is present.

getMenuInflater().inflate(R.menu.main, menu);

return true;

}

}

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