这个SQLite程序哪里出错了，如何还是有错

这个SQLite程序哪里出错了，怎么还是有错？
package com.haii.android;

import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;

public class SQLiteTestActivity extends Activity {
  OnClickListener listener_add=null;
  OnClickListener listener_update=null;
  OnClickListener listener_delete=null;
  OnClickListener listener_clear=null;
  Button button_add;
  Button button_update;
  Button button_delete;
  Button button_clear;
  DBConnection helper;
  public int id_this;
  public interface UserSchema{
String TABLE_NAME="Users";
String ID="_id";
String USER_NAME="user_name";
String ADDRESS="address";
String TELEPHONE="telephone";
String MAIL_ADDRESS="mail_address";
  }
  /** Called when the activity is first created. */
  @Override
  public void onCreate(final Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  // getIntent().setData(Uri.parse("content://com.haii.provider.testprovider"));
  // final Uri uri_test=getIntent().getData();
  setContentView(R.layout.main);
  final EditText mEditText01=(EditText)findViewById(R.id.editText1);
  final EditText mEditText02=(EditText)findViewById(R.id.editText2);
  final EditText mEditText03=(EditText)findViewById(R.id.editText3);
  final EditText mEditText04=(EditText)findViewById(R.id.editText4);
  helper=new DBConnection(this);
  final SQLiteDatabase db=helper.getWritableDatabase();
  final String[] FROM={
  UserSchema.ID,
  UserSchema.USER_NAME,
  UserSchema.TELEPHONE,
  UserSchema.ADDRESS,
  UserSchema.MAIL_ADDRESS
  };
  Cursor c=db.query(UserSchema.TABLE_NAME, new String[]{UserSchema.USER_NAME}, null,null,null,null,null);
  // Cursor c=managedQuery(uri_test,new String[]{UserSchema.USER_NAME},null,null,null);
  c.moveToFirst();
  CharSequence[] list=new CharSequence[c.getCount()];
  for(int i=0;i<list.length;i++){
  list[i]=c.getString(0);
  c.moveToNext();
  }
  c.close();
  Spinner spinner=(Spinner)findViewById(R.id.spinner1); 
  spinner.setAdapter(new ArrayAdapter<CharSequence>(this,android.R.layout.simple_spinner_item,list));
  spinner.setOnItemSelectedListener(new OnItemSelectedListener(){

@Override
public void onItemSelected(AdapterView<?> parent, View view,
int position, long id) {
String user_name=((Spinner)parent).getSelectedItem().toString();
//Cursor c=managedQuery(uri_test,FROM,"user_name='"+user_name+"'",null,null);

Cursor c=db.query("Users", FROM, "user_name='"+user_name+"'", null,null,null,null);
c.moveToFirst();
id_this=Integer.parseInt(c.getString(0));
String user_name_this=c.getString(1);
String telephone_this=c.getString(2);
String address_this=c.getString(3);