android获取加速度传感器的程序问题

android获取加速度传感器的程序问题
我现在想获取手机中的加速度传感器的变化值,并将它存入txt文档中,程序应该不难,但是我写出来发现文件穿件不出来,
代码如下 ：
package com.example.getsensorvalue;
import java.io.*;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.os.Environment;
import android.app.Activity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
\x05private SensorManager Sm;
\x05private String a="";
\x05private String b="";
\x05private TextView TV1;
\x05private Button Button1;
\x05private Button Button2;
\x05private File fos=null;
\x05private Writer out=null;
\x05@Override
\x05protected void onCreate(Bundle savedInstanceState) {
\x05\x05super.onCreate(savedInstanceState);
\x05\x05setContentView(R.layout.activity_main);
\x05\x05TV1=(TextView)findViewById(R.id.TV1);
\x05\x05Button1=(Button)findViewById(R.id.Button1);
\x05\x05Button1.setText(R.string.Button1);
\x05\x05Button2=(Button)findViewById(R.id.Button2);
\x05\x05Button2.setText(R.string.Button2);
\x05\x05Sm=(SensorManager)getSystemService(SENSOR_SERVICE);
\x05\x05Sensor Accelerate=Sm.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
\x05\x05
\x05\x05Sm.registerListener(new SensorEventListener() {
\x05\x05\x05
\x05\x05\x05@Override
\x05\x05\x05public void onSensorChanged(SensorEvent event) {
\x05\x05\x05\x05// TODO Auto-generated method stub
\x05\x05\x05\x05b=b+event.values[0]+" "+event.values[1]+" "+event.values[2]+"\n";
\x05\x05\x05\x05a=event.values[0]+" "+event.values[1]+" "+event.values[2]+"\n";
\x05\x05\x05\x05TV1.setText(a);\x05\x05\x05\x05
\x05\x05\x05}
\x05\x05\x05
\x05\x05\x05@Override
\x05\x05\x05public void onAccuracyChanged(Sensor sensor,int accuracy) {
\x05\x05\x05\x05// TODO Auto-generated method stub
\x05\x05\x05\x05
\x05\x05\x05}
\x05\x05},Accelerate,SensorManager.SENSOR_DELAY_NORMAL);
\x05\x05Button1.setOnClickListener(new OnClickListener() {\x05\x05
\x05\x05\x05@Override
\x05\x05\x05public void onClick(View v) {
\x05\x05\x05\x05// TODO Auto-generated method stub
\x05\x05\x05\x05b="";\x05\x05\x05\x05\x05\x05\x05\x05
\x05\x05\x05}
\x05\x05});
\x05\x05Button2.setOnClickListener(new OnClickListener() {\x05\x05
\x05\x05\x05@Override
\x05\x05\x05public void onClick(View v) {
\x05\x05\x05\x05// TODO Auto-generated method stub
\x05\x05\x05\x05try{
\x05\x05\x05\x05\x05fos=new File(Environment.getExternalStorageDirectory().getPath() +"accelerate.txt");
\x05\x05\x05\x05\x05fos.delete();
\x05\x05\x05\x05\x05fos.createNewFile();
\x05\x05\x05\x05\x05out=new FileWriter(fos);
\x05\x05\x05\x05\x05out.write(b);
\x05\x05\x05\x05\x05out.close();\x05\x05\x05\x05\x05
\x05\x05\x05\x05\x05}
\x05\x05\x05\x05\x05catch(Exception e){
\x05\x05\x05\x05\x05System.out.println(e);
\x05\x05\x05\x05\x05}
\x05\x05\x05}
\x05\x05});
\x05}
\x05@Override
\x05public boolean onCreateOptionsMenu(Menu menu) {
\x05\x05// Inflate the menu; this adds items to the action bar if it is present.
\x05\x05menu.add(0,1,1,R.string.exit);
\x05\x05getMenuInflater().inflate(R.menu.main,menu);
\x05\x05return true;\x05
\x05}
\x05@Override
\x05public boolean onContextItemSelected(MenuItem item) {
\x05\x05// TODO Auto-generated method stub
\x05\x05if(item.getItemId()==1){
\x05\x05\x05finish();
\x05\x05}
\x05\x05return super.onContextItemSelected(item);
\x05}
}

fos=new File(Environment.getExternalStorageDirectory().getPath() +"accelerate.txt");
路径错误
应该是fos=new File(Environment.getExternalStorageDirectory().getPath() +"/accelerate.txt");