如何在Android中同时收集多个传感器数据并将其写入文件？

Question

Below is the class that I wrote to capture and write the list of sensors on a device and corresponding sensor data.
The only problem is in the method writeSensorData() , code executes till before onSensorChanged() . Hence no data is being logged on to the corresponding text file.

A help with the code would be really helpful.

AndroidSensorList.java

package com.example.androidsensorlist;


import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import android.app.ListActivity;
import android.content.Context;
//import android.content.Intent;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorListener;
//import android.hardware.SensorListener;
import android.hardware.SensorManager;
import android.widget.ArrayAdapter;

public class AndroidSensorList extends ListActivity {
    public static final String file = ("data.txt");
    public static  File myData = null;
    public static  File myDataCollection = null;
    public static final String DATA_COLLECTION_FILE = ("DataCollection.txt");
    public SensorEventListener mSensorListener ; 
    public SensorManager sensorManager;
    public List<Sensor> listSensor;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //creating Folder on device

        String newFolder = "/myFolder2";
        String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
        File myNewFolder = new File(extStorageDirectory + newFolder);
        myNewFolder.mkdir();

        myData = new File(extStorageDirectory + newFolder + "/"+ file);
        try{
            if(!myData.exists()){
                myData.createNewFile();
            } 
        }catch(IOException ioExp){
            Log.d("AndroidSensorList::", "error in file creation");
        }

        myDataCollection = new File(extStorageDirectory + newFolder + "/"+ DATA_COLLECTION_FILE);
        try{
            if(!myDataCollection.exists()){
                myDataCollection.createNewFile();
            } 
        }catch(IOException ioExp){
            Log.d("AndroidSensorList::", "error in file creation");
        }

        //retrieving the list of sensors available on a device
        sensorManager
        = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
        listSensor
        = sensorManager.getSensorList(Sensor.TYPE_ALL);
        sensorManager.registerListener(mSensorListener, sensorManager.getDefaultSensor(Sensor.TYPE_ALL), SensorManager.SENSOR_DELAY_NORMAL);

        //Creating List view and writing data to a file

        List<String> listSensorType = new ArrayList<String>();
        for(int i=0; i<listSensor.size(); i++){
            System.out.println("Inside list sensors:::::::");
            listSensorType.add((i+1)+" "+listSensor.get(i).getName());
            String sensorNames = listSensor.get(i).getName();
            System.out.println(listSensor.get(i).getType());
            //mSensorManager.registerListener(mSensorListener, mSensorManager.getDefaultSensor(listSensor.get(i).getType()), SensorManager.SENSOR_DELAY_NORMAL);
            writeToFile(listSensor.get(i).getName().getBytes(),sensorNames );

        }

        setListAdapter(new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1,
                listSensorType));
        getListView().setTextFilterEnabled(true);
    }





    private void writeSensorData(final String sensorName) {
        System.out.println("------------------Inside writeSensorData() ----------------");
        System.out.println("Sensor Name::"+sensorName);
        //sensorManager.registerListener(mSensorListener, sensorManager.getDefaultSensor(Sensor.TYPE_ALL), SensorManager.SENSOR_DELAY_NORMAL);
        //final SensorEventListener mSensorListener = null;
        mSensorListener= new SensorEventListener(){



            @Override
            public void onSensorChanged(SensorEvent event) {
                System.out.println("++++++++++++++++INSIDE onSensorChanged() ++++++++++++++++++++++");
                System.out.println("sensorName:"+sensorName);
                System.out.println("event.sensor.getName():"+event.sensor.getName());
                if(sensorName.equalsIgnoreCase(event.sensor.getName())){
                    float x,y,z;
                    x=event.values[0];
                    y=event.values[1];
                    z=event.values[2];
                    System.out.println(sensorName+"::"+"X="+x+"Y="+y+"Z="+z);
                    //sensorManager.registerListener(mSensorListener, sensorManager.getDefaultSensor(event.sensor.getType()), SensorManager.SENSOR_DELAY_NORMAL);
                    String xVal= String.valueOf(x);
                    String yVal= String.valueOf(y);
                    String zVal= String.valueOf(z);
                    byte[] bX_Value= xVal.getBytes();
                    byte[] bY_Value= yVal.getBytes();
                    byte[] bZ_Value= zVal.getBytes();
                    String newLine = "\n";
                    byte[] bnewLine = newLine.getBytes();   
                    byte[] bSensorName = sensorName.getBytes();
                    try{
                    OutputStream fo = new FileOutputStream(myDataCollection,true);
                    fo.write(bnewLine);
                    fo.write(bSensorName);
                    fo.write(bX_Value);
                    fo.write(bY_Value);
                    fo.write(bZ_Value);
                    fo.write(bnewLine);
                    fo.close();
                    }catch(IOException e){
                        Log.e("AndroidSensorList::","File write failed: " + e.toString());
                    }
                }

            }
            @Override
            public void onAccuracyChanged(Sensor sensor, int accuracy) {
                //no need to override

            }

        };


    }





    private void writeToFile(byte[] data, String sensorNames) {
        System.out.println("----------------Inside writeToFile-----------------");
        writeSensorData(sensorNames);
        try {
            String comma = "\n";
            byte[] bComma = comma.getBytes();          
            OutputStream fo = new FileOutputStream(myData,true);  
            fo.write(bComma);
            fo.write(data);
            fo.close();

        }
        catch (IOException e) {
            Log.e("AndroidSensorList::","File write failed: " + e.toString());
        } 

    }


    protected void onResume() {
        super.onResume();
        sensorManager.registerListener(mSensorListener, sensorManager.getDefaultSensor(Sensor.TYPE_ALL), SensorManager.SENSOR_DELAY_NORMAL);
    }

    @Override
    protected void onPause() {
        sensorManager.unregisterListener(mSensorListener);
        super.onPause();

    }
}

Answer 1

Here is what I came up with to collect all the sensor data simultaneously and writing it to a file.

public class AndroidSensorList extends ListActivity implements SensorEventListener {

    //global variables
    public static final String file = ("data.txt");
    public static  File myData = null;
    public static  File myDataCollection = null;
    public static final String DATA_COLLECTION_FILE = ("DataCollection.txt");
    public SensorEventListener mSensorListener ; 
    public SensorManager sensorManager;
    public List<Sensor> listSensor;
    private  Sensor mAccelerometer,mProximity, mAmbientTemp, mGameRotationVect, mGeomagneticRotationVecor, mGravity, mGyroscope,
    mGyroUncal, mLight, mLinearAcceleration, mMagFld, mMagFldUncal, mOrientation, mPressure, mRelativeHumid, mRotVect,
    mSignificantMotion, mStepCntr, mStepDetect, mTemp;






    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //creating Folder on device

        String newFolder = "/myFolder2";
        String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
        File myNewFolder = new File(extStorageDirectory + newFolder);
        myNewFolder.mkdir();

        myData = new File(extStorageDirectory + newFolder + "/"+ file);
        try{
            if(!myData.exists()){
                myData.createNewFile();
            } 
        }catch(IOException ioExp){
            Log.d("AndroidSensorList::", "error in file creation");
        }

        myDataCollection = new File(extStorageDirectory + newFolder + "/"+ DATA_COLLECTION_FILE);
        try{
            if(!myDataCollection.exists()){
                myDataCollection.createNewFile();
            } 
        }catch(IOException ioExp){
            Log.d("AndroidSensorList::", "error in file creation");
        }

        //retrieving the list of sensors available on a device
        sensorManager
        = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
        listSensor
        = sensorManager.getSensorList(Sensor.TYPE_ALL);
        mAccelerometer=sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        mAmbientTemp=sensorManager.getDefaultSensor(Sensor.TYPE_AMBIENT_TEMPERATURE);
        mGameRotationVect=sensorManager.getDefaultSensor(Sensor.TYPE_GAME_ROTATION_VECTOR);
        mGeomagneticRotationVecor=sensorManager.getDefaultSensor(Sensor.TYPE_GEOMAGNETIC_ROTATION_VECTOR);
        mGravity=sensorManager.getDefaultSensor(Sensor.TYPE_GRAVITY);
        mGyroscope=sensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
        mGyroUncal=sensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE_UNCALIBRATED);
        mLight=sensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
        mLinearAcceleration=sensorManager.getDefaultSensor(Sensor.TYPE_LINEAR_ACCELERATION);
        mMagFld=sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
        mMagFldUncal=sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD_UNCALIBRATED);
        mOrientation=sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
        mPressure=sensorManager.getDefaultSensor(Sensor.TYPE_PRESSURE);
        mProximity=sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
        mRelativeHumid=sensorManager.getDefaultSensor(Sensor.TYPE_RELATIVE_HUMIDITY);
        mRotVect=sensorManager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR);
        mSignificantMotion=sensorManager.getDefaultSensor(Sensor.TYPE_SIGNIFICANT_MOTION);
        mStepCntr=sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
        mStepDetect=sensorManager.getDefaultSensor(Sensor.TYPE_STEP_DETECTOR);
        mTemp=sensorManager.getDefaultSensor(Sensor.TYPE_TEMPERATURE);

        //Creating List view and writing data to a file

        List<String> listSensorType = new ArrayList<String>();
        for(int i=0; i<listSensor.size(); i++){
            System.out.println("Inside list sensors:::::::");
            listSensorType.add((i+1)+" "+listSensor.get(i).getName());
            String sensorNames = listSensor.get(i).getName();
            System.out.println(listSensor.get(i).getType());
            //mSensorManager.registerListener(mSensorListener, mSensorManager.getDefaultSensor(listSensor.get(i).getType()), SensorManager.SENSOR_DELAY_NORMAL);
            writeToFile(listSensor.get(i).getName().getBytes(),sensorNames );

        }

        setListAdapter(new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1,
                listSensorType));
        getListView().setTextFilterEnabled(true);
    }


    private void writeToFile(byte[] data, String sensorNames) {
        System.out.println("----------------Inside writeToFile-----------------");

        try {
            String comma = "\n";
            byte[] bComma = comma.getBytes();          
            OutputStream fo = new FileOutputStream(myData,true);  
            fo.write(bComma);
            fo.write(data);
            fo.close();

        }
        catch (IOException e) {
            Log.e("AndroidSensorList::","File write failed: " + e.toString());
        } 

    }


    protected void onResume() {
        super.onResume();
        sensorManager.registerListener(this,mAccelerometer,  SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, mProximity, SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this,mAmbientTemp,  SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, mGameRotationVect, SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this,mGeomagneticRotationVecor,  SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, mGravity,  SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, mGyroscope, SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, mGyroUncal, SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, mLight,  SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, mLinearAcceleration, SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this,mMagFld,  SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this,mMagFldUncal,  SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this,mOrientation,   SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this,mPressure,   SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, mRelativeHumid, SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this,mRotVect,  SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, mSignificantMotion, SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this,mStepCntr,   SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, mStepDetect, SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, mTemp, SensorManager.SENSOR_DELAY_NORMAL);
        }

    @Override
    protected void onPause() {
        sensorManager.unregisterListener(mSensorListener);
        super.onPause();

    }





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

    }





    @Override
    public void onSensorChanged(SensorEvent event) {
        // TODO Auto-generated method stub
        System.out.println("++++++++++++++++INSIDE onSensorChanged() ++++++++++++++++++++++");
        //System.out.println("sensorName:"+sensorName);
        System.out.println("event.sensor.getName():"+event.sensor.getName());
        float x,y,z;

        x=event.values[0];
        y=event.values[1];
        z=event.values[2];
        writeDataTofile(event.sensor.getName(),x,y,z);

    }
    public void writeDataTofile(String sensorsName, float x, float y, float z){

        System.out.println(sensorsName+"::"+"X="+x+"Y="+y+"Z="+z);

        //mSensorManager.registerListener(mSensorListener, mSensorManager.getDefaultSensor(event.sensor.getType()), SensorManager.SENSOR_DELAY_NORMAL);
        String xVal= String.valueOf(x);
        String yVal= String.valueOf(y);
        String zVal= String.valueOf(z);
        byte[] bX_Value= xVal.getBytes();
        byte[] bY_Value= yVal.getBytes();
        byte[] bZ_Value= zVal.getBytes();
        String newLine = "\n";
        byte[] bnewLine = newLine.getBytes();   
        String sSeparator="||";
        byte[] bSeparator=sSeparator.getBytes();
        byte[] bSensorName = sensorsName.getBytes();
        try{
        OutputStream fo = new FileOutputStream(myDataCollection,true);
        fo.write(bnewLine);
        fo.write(bSensorName);
        fo.write(bX_Value);
        fo.write(bSeparator);
        fo.write(bY_Value);
        fo.write(bSeparator);
        fo.write(bZ_Value);
        fo.write(bnewLine);
        fo.close(); 
        }catch(IOException e){
            Log.e("AndroidSensorList::","File write failed: " + e.toString());
        }
    }
}