Android开发需要运用到哪5类

public class Person {

 private int _id;
 private String name;

 public int getId() {
  return _id;
 }

 public void setId(int _id) {
  this._id = _id;
 }

 public String getName() {
  return name;
 }

 public void setName(String name) {
  this.name = name;
 }

 @Override
 public String toString() {
  return "Person [id=" + _id + ", name=" + name + "]";
 }

 public Person() {
  super();
 }

 public Person(int _id, String name) {
  super();
  this._id = _id;
  this.name = name;
 }
}

import java.util.List;

/**
 * 增删改查
 * @author ZLQ
 *
 */
public interface SQLOperate {
 public void add(Person p);
 public void delete(int id);
 public void updata(Person p);
 public List find();
 public Person findById(int id);
}

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

/**
 * 助手类
 * @author ZLQ
 *
 */
public class DBOpneHelper extends SQLiteOpenHelper {

 private static final int VERSION = 1;//版本
 private static final String DB_NAME = "people.db";//数据库名
 public static final String STUDENT_TABLE = "student";//表名
 public static final String _ID = "_id";//表中的列名
 public static final String NAME = "name";//表中的列名
 //创建数据库语句，STUDENT_TABLE，_ID ，NAME的前后都要加空格
 private static final String CREATE_TABLE = "create table " + STUDENT_TABLE + " ( " + _ID + " Integer primary key autoincrement," + NAME + " text)";

 public DBOpneHelper(Context context) {
  super(context, DB_NAME, null, VERSION);
 }

 //数据库第一次被创建时调用
 @Override
 public void onCreate(SQLiteDatabase db) {
  db.execSQL(CREATE_TABLE);
 }

 //版本升级时被调用
 @Override
 public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

 }

}

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 SQLOperateImpl implements SQLOperate{

 private DBOpneHelper dbOpenHelper;

 public SQLOperateImpl(Context context) {
  dbOpenHelper = new DBOpneHelper(context);
 }

 /**
  * 增，用insert向数据库中插入数据
  */
 public void add(Person p) {
  SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
  ContentValues values = new ContentValues();
  values.put(DBOpneHelper._ID, p.getId());
  values.put(DBOpneHelper.NAME, p.getName());
  db.insert(DBOpneHelper.STUDENT_TABLE, null, values);
 }

 /**
  * 删，通过id删除数据
  */
 public void delete(int id) {
  SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
  db.delete(DBOpneHelper.STUDENT_TABLE, DBOpneHelper._ID + "=?", new String[]{String.valueOf(id)});
 }

 /**
  * 改，修改指定id的数据
  */
 public void updata(Person p) {
  SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
  ContentValues values = new ContentValues();
  values.put(DBOpneHelper._ID, p.getId());
  values.put(DBOpneHelper.NAME, p.getName());
  db.update(DBOpneHelper.STUDENT_TABLE, values, DBOpneHelper._ID + "=?", new String[]{String.valueOf(p.getId())});
 }

 /**
  * 查，查询表中所有的数据
  */
 public List find() {
  List persons = null;
  SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
  Cursor cursor = db.query(DBOpneHelper.STUDENT_TABLE, null, null, null, null, null, null);
  if(cursor != null){
   persons = new ArrayList();
   while(cursor.moveToNext()){
    Person person = new Person();
    int _id = cursor.getInt(cursor.getColumnIndex(DBOpneHelper._ID));
    String name = cursor.getString(cursor.getColumnIndex(DBOpneHelper.NAME));
    person.setId(_id);
    person.setName(name);
    persons.add(person);
   }
  }
  return persons;
 }

 /**
  * 查询指定id的数据
  */
 public Person findById(int id) {
  SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
  Cursor cursor = db.query(DBOpneHelper.STUDENT_TABLE, null, DBOpneHelper._ID + "=?", new String[]{String.valueOf(id)}, null, null, null);
  Person person = null;
  if(cursor != null && cursor.moveToFirst()){
   person = new Person();
   int _id = cursor.getInt(cursor.getColumnIndex(DBOpneHelper._ID));
   String name = cursor.getString(cursor.getColumnIndex(DBOpneHelper.NAME));
   person.setId(_id);
   person.setName(name);
  }
  return person;
 }
}

import java.util.List;

import android.test.AndroidTestCase;
import android.util.Log;

public class Test extends AndroidTestCase {
 public void testAdd() throws Exception{
  SQLOperateImpl test = new SQLOperateImpl(getContext());
  Person person = new Person(2, "Peter");
  test.add(person);
 }

 public void testDelete() throws Exception{
  SQLOperateImpl test = new SQLOperateImpl(getContext());
  test.delete(1);
 }

 public void testUpdata() throws Exception{
  SQLOperateImpl test = new SQLOperateImpl(getContext());
  Person person = new Person(1, "Tom");
  test.updata(person);
 }

 public void testFind() throws Exception{
  SQLOperateImpl test = new SQLOperateImpl(getContext());
  List persons = test.find();
  for (Person person : persons) {
   Log.i("System.out", person.toString());
  }
 }

 public void testFindById() throws Exception{
  SQLOperateImpl test = new SQLOperateImpl(getContext());
  Person person = test.findById(2);
  Log.i("System.out", person.toString());
 }
}