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我正在编写一个应用程序，我必须在其中将数据存储在加速度计值的文件中。我怎么做 ？我只需要创建一次文件并将数据附加到该文件中。这是申请流程：

  1. 用户单击开始按钮，它应该开始将传感器数据写入文件。
  2. 用户单击停止按钮，它应该停止将数据写入文件。

请帮助..

编辑 1：根据@iTech 编写代码，但不附加数据。

import java.io.*;
import java.util.ArrayList;
import java.util.List;

import app.AccelLocData;

import com.google.android.gms.maps.*;
import com.google.android.gms.maps.GoogleMap.OnMapClickListener;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.Dialog;
import android.content.Context;

import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;

import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

public class MapViewActivity extends Activity implements LocationListener,
        SensorEventListener, OnClickListener {

    GoogleMap googleMap;

    private boolean started = false;
    private ArrayList<AccelLocData> sensorData;
    private SensorManager sensorManager;
    private Button btnStart, btnStop;
    private String provider;

    File root, dir, sensorFile;
    FileOutputStream fOut;
    // ObjectOutputStream myOutWriter;
    private Sensor mAccelerometer;
    private FileWriter writer;

    // private Button btnUpload;

    @SuppressLint("NewApi")
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        try {
            root = android.os.Environment.getExternalStorageDirectory();
            dir = new File(root.getAbsolutePath() + "/myapp");
            dir.mkdirs();

            File oldFile = new File(dir, "data.txt");

            boolean deleted = oldFile.delete();
            System.out.println("Delete status = " + deleted);
            sensorFile = new File(dir, "data.txt");

            sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
            mAccelerometer = sensorManager
                    .getDefaultSensor(Sensor.TYPE_ACCELEROMETER);


            btnStart = (Button) findViewById(R.id.btnStart);
            btnStop = (Button) findViewById(R.id.btnStop);
            btnStart.setOnClickListener(this);
            btnStop.setOnClickListener(this);
            btnStart.setEnabled(true);
            btnStop.setEnabled(false);

            int status = GooglePlayServicesUtil
                    .isGooglePlayServicesAvailable(getBaseContext());
            if (status != ConnectionResult.SUCCESS) { // Google Play Services
                                                        // are
                                                        // not available

                int requestCode = 10;
                Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status,
                        this, requestCode);
                dialog.show();

            } else { // Google Play Services are available

                // Getting reference to the SupportMapFragment of
                // activity_main.xml
                // SupportMapFragment supportMapFragment = (MapFragment)
                // getFragmentManager().findFragmentById(R.id.map);

                // Getting GoogleMap object from the fragment
                googleMap = ((MapFragment) getFragmentManager()
                        .findFragmentById(R.id.map)).getMap();
                // googleMap = supportMapFragment.getMap();

                // can use for overlay on the map
                List<Double> latList = new ArrayList<Double>();
                latList.add(45.7309593);
                latList.add(46.34);
                latList.add(47.34);

                List<Double> lonList = new ArrayList<Double>();
                lonList.add(-122.6365384);
                lonList.add(-123.6365384);
                lonList.add(-124.6365384);

                for (int i = 0; i < 3; i++) {
                    // LatLng latLng = new LatLng(45.7309593, -122.6365384);
                    LatLng latLng = new LatLng(latList.get(i).doubleValue(),
                            lonList.get(i).doubleValue());
                    googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
                    googleMap
                            .addMarker(new MarkerOptions()
                                    .position(latLng)
                                    .title("My Spot")
                                    .snippet("This is my spot!")
                                    .icon(BitmapDescriptorFactory
                                            .defaultMarker(BitmapDescriptorFactory.HUE_AZURE)));
                }
                googleMap.setOnMapClickListener(new OnMapClickListener() {

                    @Override
                    public void onMapClick(LatLng latLng) {

                        // Creating a marker
                        MarkerOptions markerOptions = new MarkerOptions();

                        // Setting the position for the marker
                        markerOptions.position(latLng);

                        // Setting the title for the marker.
                        // This will be displayed on taping the marker
                        markerOptions.title(latLng.latitude + " : "
                                + latLng.longitude);

                        // Clears the previously touched position
                        googleMap.clear();

                        // Animating to the touched position
                        googleMap.animateCamera(CameraUpdateFactory
                                .newLatLng(latLng));

                        // Placing a marker on the touched position
                        googleMap.addMarker(markerOptions);
                    }
                });

                // Enabling MyLocation Layer of Google Map
                googleMap.setMyLocationEnabled(true);

                LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

                Criteria criteria = new Criteria();
                provider = locationManager.getBestProvider(criteria, true);
                Location location = locationManager
                        .getLastKnownLocation(provider);

                if (location != null) {
                    onLocationChanged(location);
                }

                locationManager
                        .requestLocationUpdates(provider, 20000, 0, this);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    public void onSensorChanged(SensorEvent event) {

        if (started) {

            double x = event.values[0];
            double y = event.values[1];
            double z = event.values[2];

            long timestamp = System.currentTimeMillis();

            LocationManager locManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
            Criteria criteria = new Criteria();
            criteria.setPowerRequirement(Criteria.POWER_MEDIUM);
            criteria.setAccuracy(Criteria.ACCURACY_FINE);

            provider = locManager.getBestProvider(criteria, true);
            Location location = locManager.getLastKnownLocation(provider);

            double latitude = 0;
            double longitude = 0;
            if (location != null) {
                latitude = location.getLatitude();
                longitude = location.getLongitude();
            }
            AccelLocData data = new AccelLocData(timestamp, x, y, z, latitude,
                    longitude);

            System.out.println("data x:" + data.getX());

            try {
                writer.write(data.toString());
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    }

    @Override
    public void onLocationChanged(Location location) {

        TextView tvLocation = (TextView) findViewById(R.id.tv_location);

        // Getting latitude of the current location
        double latitude = location.getLatitude();

        // Getting longitude of the current location
        double longitude = location.getLongitude();

        // Creating a LatLng object for the current location
        LatLng latLng = new LatLng(latitude, longitude);

        // Showing the current location in Google Map
        googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));

        // Zoom in the Google Map
        googleMap.animateCamera(CameraUpdateFactory.zoomTo(15));
        // System.out.println("Latitude:" + latitude + ", Longitude:" +
        // longitude);

        // Setting latitude and longitude in the TextView tv_location
        // tvLocation.setText("Latitude:" + latitude + ", Longitude:" +
        // longitude);

    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.btnStart:

            btnStart.setEnabled(false);
            btnStop.setEnabled(true);
            System.out.println("cam on click of start");
            started = true;

            sensorManager.registerListener(this, mAccelerometer,
                    SensorManager.SENSOR_DELAY_FASTEST);
            break;
        case R.id.btnStop:
            try {
                btnStart.setEnabled(true);
                btnStop.setEnabled(false);
                // btnUpload.setEnabled(true);
                started = false;

                sensorManager.unregisterListener(this);

                /*
                 * if(writer != null) { try { writer.close(); } catch
                 * (IOException e) { // TODO Auto-generated catch block
                 * e.printStackTrace(); } }
                 */} catch (Exception e) {
                e.printStackTrace();
            }
            break;
        default:
            break;
        }

    }

    protected void onPause() {
        super.onPause();

        if (writer != null) {
            try {
                writer.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    protected void onResume() {
        super.onResume();
        try {
            System.out.println("called onresume");
            writer = new FileWriter(sensorFile, true);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    @Override
    public void onProviderDisabled(String arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub

    }

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

    }

}
4

1 回答 1

3

这是一个示例代码供您入门。

您可以查看 android 示例以了解如何从传感器读取数据，然后将其写入文件。

要运行此代码，您需要添加两个按钮并将它们设置onClick为onStartClick和onStopClick。您还可以指定要在 SD 卡上的输出文件路径。

public class Main extends Activity implements SensorEventListener {

private SensorManager mSensorManager;
private Sensor mAccelerometer;
private FileWriter writer;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activiy_main);
    mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
    mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
}

public void onStartClick(View view) {
    mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);
}

public void onStopClick(View view) {
    mSensorManager.unregisterListener(this);
}
protected void onResume() {
    super.onResume();
    writer = new FileWriter("myfile.txt",true);
}

protected void onPause() {
    super.onPause();

    if(writer != null) {
       writer.close();
    }
}

@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {

}

@Override
public void onSensorChanged(SensorEvent event) {

    float x = event.values[0];
    float y = event.values[1];
    float z = event.values[2];
    writer.write(x+","+y+","+z+"\n");

 }
}
于 2013-04-28T22:20:33.557 回答