BD.java

package br.exemplosqlite;

import java.util.ArrayList;
import java.util.List;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

public class BD {
	private SQLiteDatabase bd;
	
	public BD(Context context){
		BDCore auxBd = new BDCore(context);
		bd = auxBd.getWritableDatabase();
	}
	
	
	public void inserir(Usuario usuario){
		ContentValues valores = new ContentValues();
		valores.put("nome", usuario.getNome());
		valores.put("email", usuario.getEmail());
		valores.put("senha", usuario.getSenha());
		
		bd.insert("usuario", null, valores);
	}
	
	
	public void atualizar(Usuario usuario){
		ContentValues valores = new ContentValues();
		valores.put("nome", usuario.getNome());
		valores.put("email", usuario.getEmail());
		
		bd.update("usuario", valores, "_id = ?", new String[]{""+usuario.getId()});
	}
	
	
	public void deletar(Usuario usuario){
		bd.delete("usuario", "_id = "+usuario.getId(), null);
	}
	
	
	public List<Usuario> buscar(){
		List<Usuario> list = new ArrayList<Usuario>();
		String[] colunas = new String[]{"_id", "nome", "email"};
		
		Cursor cursor = bd.query("usuario", colunas, null, null, null, null, "nome ASC");
		
		if(cursor.getCount() > 0){
			cursor.moveToFirst();
			
			do{
				
				Usuario u = new Usuario();
				u.setId(cursor.getLong(0));
				u.setNome(cursor.getString(1));
				u.setEmail(cursor.getString(2));
				list.add(u);
				
			}while(cursor.moveToNext());
		}
		
		return(list);
	}
}

BDCore.java

package br.exemplosqlite;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class BDCore extends SQLiteOpenHelper {
	private static final String NOME_BD = "teste";
	private static final int VERSAO_BD = 7;
	
	
	public BDCore(Context ctx){
		super(ctx, NOME_BD, null, VERSAO_BD);
	}
	
	
	@Override
	public void onCreate(SQLiteDatabase bd) {
		bd.execSQL("create table usuario(_id integer primary key autoincrement, nome text not null, email text not null, senha text not null);");
	}

	@Override
	public void onUpgrade(SQLiteDatabase bd, int arg1, int arg2) {
		bd.execSQL("drop table usuario;");
		onCreate(bd);
	}

}