Android activity stops working when reading files from /data/data

Question

My android application is kind of a text editor. I want to display the list of saved files. But whenever the activity listing the files is called, the activity stops. This code works completely fine when run in emulator but not on the actual device. Debugging the application on phone shows that the app stops when it tries to access the path although no error is displayed in logcat.

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.graphics.drawable.Drawable;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class File_List extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);             
        setContentView(R.layout.file_list);

        Drawable background=getResources().getDrawable(R.drawable.background);              
                background.setAlpha(100);

            final ListView list=(ListView)findViewById(R.id.listView1);

             File folder = new File("/data/data/com.example.demo/files");   //for accessing the folder conatining the files
                File[] listOfFiles = folder.listFiles();                //for listing the files within the folder

                ArrayList<String> liste = new ArrayList<String>();


             for(int i=0;i<listOfFiles.length;i++)

             {

                    if(listOfFiles[i].isDirectory()==false)

                        liste.add(listOfFiles[i].getName());

             }

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, liste);

        list.setAdapter(adapter);

        list.setOnItemClickListener(new OnItemClickListener()
        {

            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int position,long arg3) 
            {
                // TODO Auto-generated method stub
                //Log.e("selected",list.getAdapter().getItem(position).toString());

                Common.CommonVar=2;

                File file=new File("/data/data/com.example.demo/files/"+list.getAdapter().getItem(position).toString());
                String content;
                Log.e("file access", file.getName());
                try 
                {
                    content = new Scanner(file).useDelimiter("\\A").nextLine();
                    Intent intent=new Intent(File_List.this,MainActivity.class);  
                    intent.putExtra("File_data",content);
                    startActivity(intent);
                } 
                catch (FileNotFoundException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }


            }

        });   
    }   
}   

Answer 1

Change the line as follows

File folder = new File("/data/data/com.example.demo/files");   
if(!folder.exists()){
    folder.mkdir();
}