Android基础之十五数据存储之 SQLite数据库的封装

最新推荐文章于 2024-12-24 22:56:53 发布

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#数据库 #android #数据存储 #SQLite数据库的封装 #封装

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本文主要探讨了Android中SQLite数据库的封装技术，包括如何创建、操作数据库以及优化数据存储过程，旨在提供一种高效的数据管理解决方案。

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SQLite数据库的封装

一：建立实体类对象，字段名一定要和数据库里的一一对应

Book.java

<span style="font-size:14px;">package com.example.entity;

public class Book {
	private Integer  id;
	private String  author;
	private double price;
	private Integer pages;
	private String name;
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getAuthor() {
		return author;
	}
	public void setAuthor(String author) {
		this.author = author;
	}
	public double getPrice() {
		return price;
	}
	public void setPrice(double price) {
		this.price = price;
	}
	public Integer getPages() {
		return pages;
	}
	public void setPages(Integer pages) {
		this.pages = pages;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Book() {
		super();
		// TODO Auto-generated constructor stub
	}
	public Book(Integer id, String author, double price, Integer pages,
			String name) {
		super();
		this.id = id;
		this.author = author;
		this.price = price;
		this.pages = pages;
		this.name = name;
	}
	@Override
	public String toString() {
		return "Book [id=" + id + ", author=" + author + ", price=" + price
				+ ", pages=" + pages + ", name=" + name + "]";
	}	
	
}</span>

Category.java

package com.example.entity;

public class Category {
	private Integer  id;
	private String category_name;
	private Integer category_code;
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getCategory_name() {
		return category_name;
	}
	public void setCategory_name(String category_name) {
		this.category_name = category_name;
	}
	public Integer getCategory_code() {
		return category_code;
	}
	public void setCategory_code(Integer category_code) {
		this.category_code = category_code;
	}
	public Category() {
		super();
		// TODO Auto-generated constructor stub
	}
	public Category(Integer id, String category_name, Integer category_code) {
		super();
		this.id = id;
		this.category_name = category_name;
		this.category_code = category_code;
	}
	
}

二：在dao层建立数据库管理类

package com.example.sqllitehelp.dao;

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

import com.example.entity.Book;
import com.example.sqllitehelp.MainActivity;
import com.example.sqllitehelp.MyDatabaseHelper;

import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.widget.Toast;


public class sqlitedao   {
	private MyDatabaseHelper myDatabaseHlper;
	public sqlitedao(Context context) {
		myDatabaseHlper=new MyDatabaseHelper(context, "BookStore.db", null, 1);
	}
	public void add_data(Book  bk ){
		SQLiteDatabase  db=myDatabaseHlper.getWritableDatabase();
		ContentValues values=new ContentValues();
		//开始组装第一条数据
		values.put("name", bk.getName());
		values.put("author", bk.getAuthor());
		values.put("pages",bk.getPages());
		values.put("price", bk.getPrice());
		db.insert("Book", "name", values);
		//当values参数为空或者里面没有内容的时候，
		//我们insert是会失败的（底层数据库不允许插入一个空行），为了防止这种情况，我们要在这里指定一个列名，
		//到时候如果发现将要插入的行为空行时，就会将你指定的这个列名的值设为null，然后再向数据库中插入。
	}
	//修改数据
	public void Upata_data(Book bk){
		SQLiteDatabase  db=myDatabaseHlper.getWritableDatabase();
		ContentValues values=new ContentValues();
		values.put("price",bk.getPrice() );
		db.update("Book", values, "name =?", new String []{bk.getName()+""});

	}
	//查询数据
	public  List query_data(){
		//查询Book表中的数据
		List<Book> list=new ArrayList<Book>();
		SQLiteDatabase  db=myDatabaseHlper.getWritableDatabase();
		ContentValues values=new ContentValues();
		Cursor cursor=db.query("Book", null, null, null, null, null, null);	
		if(cursor.moveToFirst()){
			//遍历cursor对象，取出数据并打印。
			do{
				Integer id=cursor.getInt(cursor.getColumnIndex("id"));
				String name=cursor.getString(cursor.getColumnIndex("name"));
				String author=cursor.getString(cursor.getColumnIndex("author"));
				double pages=cursor.getDouble(cursor.getColumnIndex("pages"));
				Integer price=cursor.getInt(cursor.getColumnIndex("price"));
				//System.out.println("名字"+name+"作者"+author+"书页"+pages+"价格"+price);
				list.add(new Book(id, author, pages, price, name));
			}while(cursor.moveToNext());				
		}
		return list;

	}
	//删除数据
	public void delete_data(Book bk){
		SQLiteDatabase  db=myDatabaseHlper.getWritableDatabase();
		ContentValues values=new ContentValues();
		db.delete("Book", "pages >?", new String []{bk.getPages()+""});
	}
}

怎么测试呢？？？？？在AndroidManifest.xml中加入

<uses-library android:name="android.test.runner"/>

具体请看：

地方

<span style="color:#333333;"><?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.sqllitehelp"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="17"
        android:targetSdkVersion="17" />
	</span><span style="color:#ff0000;"><instrumentation 
	    android:name="android.test.InstrumentationTestRunner"
	    android:targetPackage="com.example.sqllitehelp"
	    ></instrumentation></span><span style="color:#333333;">
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.sqllitehelp.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        </span><span style="color:#ff0000;"><uses-library android:name="android.test.runner"/></span><span style="color:#333333;">
    </application>

</manifest></span>

三测试操作数据库是否成功

<span style="font-size:14px;">package com.sqlitehelp.text;

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

import com.example.entity.Book;
import com.example.sqllitehelp.dao.sqlitedao;

import android.test.AndroidTestCase;

public class SqlistTest  extends AndroidTestCase{
	public void testadd(){
		sqlitedao dao=new sqlitedao(getContext());
		Book  book=new Book(1, "zhu", 12.15, 12, "codeadd");
		dao.add_data(book);
		System.out.println("添加数据成功");
	}
	public void query_add(){
		sqlitedao dao=new sqlitedao(getContext());
		List<Book> list=dao.query_data();
		System.out.println("查询数据成功"+list);
		
	}
}</span>