SQLiteDataBase（通过测试类测试写好的SQLite的相关数据库操作）

SQLiteDataBase（通过测试类测试写好的SQLite的相关数据库操作）

1.首先，创建数据库：

创建一个DbHelper.java的类

package com.example.sqldatabase;

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

/**
 * @author 郑明亮
 * @date 2015-11-13 下午8:02:27
 * @version 1.0
 * 测试看com.example.sqldatabase.test.StudentTest.java
 */
public class DbHelper extends SQLiteOpenHelper {

	
	

	/**
	 * @param context 
	 */
	public DbHelper(Context context) {
//四个参数分别为：上下文，数据库的名字，Cursor工厂，数据库的版本号（最低从1开始）
		super(context,"data.db", null, 1);
	}

	@Override
	public void onCreate(SQLiteDatabase arg0) {
		//创建数据库的一个表
		String sql = "create table student(_id integer primary key autoincrement,name varchar(20),age integer,score float)";
		arg0.execSQL(sql);

	}

	@Override
	public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
		// 只有当数据库的版本号改变时才会调用的方法

	}

}

2.然后写对数据库的增删改查：写一个dao层；

StudentDao.java

package com.example.entity.dao;

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

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

import com.example.entity.Student;
import com.example.sqldatabase.DbHelper;

/**
 * @author 郑明亮
 * @date 2015-11-13 下午8:50:03
 * @version 1.0
 */
public class StudentDao {
	DbHelper helper = null;

	public StudentDao(Context context) {
		//在构造方法中实例化的好处是，
		//当实例化StudentDao时，数据库DbHelper也进行了实例化
		helper = new DbHelper(context);
	}

	/**
	 * @param name 学生姓名
	 * @param age	年龄	
	 * @param score 分数
	 * 增加一个学生
	 */
	public void add(String name, int age, float score) {

		SQLiteDatabase db = helper.getWritableDatabase();
		db.execSQL("insert into student(name,age,score) values(?,?,?)",
				new Object[] { name, age, score });
		db.close();
	}

	/**
	 * @param id
	 * 通过id删除一个学生
	 */
	public void delete(int id) {
		SQLiteDatabase db = helper.getWritableDatabase();
		db.execSQL("delete from student where _id=?", new Object[] { id });
		db.close();
	}

	/**
	 * @param id
	 * @param name
	 * @param age
	 * @param score
	 * 通过id更新一个学生的基本信息
	 */
	public void update(int id, String name, int age, float score) {
		SQLiteDatabase db = helper.getWritableDatabase();
		db.execSQL("update student set name=? ,age=? ,score=? where _id=?",
				new Object[] { name, age, score, id });
		db.close();
	}

	/**
	 * @param id
	 * @return	返回一个学生对象；
	 * 通过id返回一个学生的信息；
	 */
	public Student findByName(int  id) {
		Student student=null;
		SQLiteDatabase db = helper.getReadableDatabase();
		
		Cursor cursor = db.rawQuery("select * from student where _id=?",
				new String[] { ""+id});
if(cursor.moveToFirst()){
		String name = cursor.getString(cursor.getColumnIndex("name"));
		int age = cursor.getInt(cursor.getColumnIndex("age"));
		float score = cursor.getFloat(cursor.getColumnIndex("score"));
		student = new Student();
		student.setName(name);
		student.setAge(age);
		student.setScore(score);}
		return student;
	}

	/**
	 * @return 返回所有的学生信息
	 */
	public List<Student> findAll() {
		List<Student> list = new ArrayList<Student>();
		SQLiteDatabase db = helper.getReadableDatabase();
		Cursor cursor = db.rawQuery("select * from student ", null);
		while (cursor.moveToNext()) {

			int id = cursor.getInt(cursor.getColumnIndex("_id"));
			String name = cursor.getString(cursor.getColumnIndex("name"));
			int age = cursor.getInt(cursor.getColumnIndex("age"));
			float score = cursor.getFloat(cursor.getColumnIndex("score"));
			Student student = new Student(id, name, age, score);
			list.add(student);
		}

		db.close();

		return list;
	}
}

3.在创建dao层时，用到了一个学生类，创建一个学生类：

Student.java

package com.example.entity;
/**
 * @author 郑明亮
 * @date 2015-11-13 下午8:47:48
 * @version 1.0
 */
public class Student {
	int id;
	public Student() {
		super();
		// TODO Auto-generated constructor stub
	}
	public Student(int id, String name, int age, float score) {
		super();
		this.id = id;
		this.name = name;
		this.age = age;
		this.score = score;
	}
	String name;
	int age;
	float score;
	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;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public float getScore() {
		return score;
	}
	public void setScore(float score) {
		this.score = score;
	}
	
	@Override
	public String toString() {
		// TODO Auto-generated method stub
		return "Id:"+id+",Name:"+name+",age:"+age+",score:"+score;
	}
}

4.准备工作做好之后，该测试写的增删改查是不是正确了，

创建一个测试类StudentTest.java：

package com.example.sqldatabase.test;

import java.util.List;

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

import com.example.entity.Student;
import com.example.entity.dao.StudentDao;

/**
 * @author 郑明亮
 * @date 2015-11-13 下午8:12:04
 * @version 1.0
 */
public class StudentTest extends AndroidTestCase {

	/**
	 * 增加一名学生
	 */
	public void AddStudent() throws Exception {

		StudentDao studentdao = new StudentDao(getContext());
		studentdao.add("小明", 27, 91);

	}

	/**
	 * 查询所有的学生
	 */
	public void findAllStudent() throws Exception {

		StudentDao studentdao = new StudentDao(getContext());
		List<Student> list = studentdao.findAll();
		for (Student s : list)
			Log.e("Student",s.toString());

	}
	
	/**
	 * 通过id查找学生信息
	 */
	public void findById(){
		StudentDao studentdao = new StudentDao(getContext());
		Student student=studentdao.findByName(1);
		System.out.println(student.toString());
	}
	/**通过id删除学生信息
	 * 
	 */
	public void deleteStudent(){
		StudentDao studentdao = new StudentDao(getContext());
		studentdao.delete(1);
	}
	
	/**
	 *通过id更新学生的基本信息 
	 */
	public void updateStudent(){
		StudentDao studentdao = new StudentDao(getContext());
		studentdao.update(2, "郑明亮修改", 100, 100);
	}
	
}

目录结构：

所有的测试都在测试类中进行即可，不太懂使用测试类（Android Junit Test），请继续往下看，

直接这样执行还是不行的，肯定会保存的，需要在AndroidManifest.xml中加两条配置，声明一下

项目下载地址：http://download.csdn.net/detail/zml_2015/9269019