Android---SQLite数据库存储

推荐使用：LitePal 这个开源库

1、新建一个继承于SQLiteOpenHelper

package com.mycompany.databasesqlite;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import android.widget.Toast;/** * Created by sstek_mars on 2017/9/1. */public class MyDatabaseHelper extends SQLiteOpenHelper {    // 建表    public static final String CREAT_BOOK = "create table book ("            + "id integer primary key autoincrement, "            + "author text, "            + "price real, "            + "pages integer, "            + "name text)";    // 建新表    public static final String CREATE_CATEGORY = "create table Category ("            + "id integer primary key autoincrement, "            + "category_name text, "            + "category_code text)";    private Context mContext;    /**     *     * @param context 必须有它才可以对数据库进行操作     * @param name 数据库名     * @param factory 参数运行我们在查询数据的时候返回一个自定义的Cursor，一般为 null     * @param version 数据库的版本号     */    public MyDatabaseHelper(Context context, String name,                            SQLiteDatabase.CursorFactory factory, int version) {        super(context, name, factory, version);        mContext = context;    }    // 创建数据库，如果已经存在了，是不会再去创建数据库    @Override    public void onCreate(SQLiteDatabase db) {        db.execSQL(CREAT_BOOK);        db.execSQL(CREATE_CATEGORY);        Toast.makeText(mContext, "创建数据库成功", Toast.LENGTH_SHORT).show();    }    // 升级数据库    // 解决在已有数据库的情况下，再新建一个新的数据库失败问题    // 必须传一个大于之前版本的数，才会执行    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {        db.execSQL("drop table if exists Book");        db.execSQL("drop table if exists Category");        onCreate(db);    }}

2、使用

package com.mycompany.databasesqlite;import android.content.ContentValues;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;public class MainActivity extends AppCompatActivity {    private MyDatabaseHelper dbHelper;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        // 第一次新建        // dbHelper = new MyDatabaseHelper(this, "BookStore.db", null, 1);        // 升级 版本号必须大于前一次版本号        dbHelper = new MyDatabaseHelper(this, "BookStore.db", null, 2);        // 新建按钮        Button createDatabase = (Button) findViewById(R.id.create_database);        createDatabase.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                dbHelper.getWritableDatabase();            }        });        // 增        Button addDatabase = (Button) findViewById(R.id.add_data);        addDatabase.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                SQLiteDatabase db = dbHelper.getWritableDatabase();                ContentValues values = new ContentValues();                // 开始组装第一条数据                values.put("name", "The da vinvi code");                values.put("author", "dan brown");                values.put("pages", 222);                values.put("price", 111);                // 插入第一条数据                db.insert("Book", null, values);                values.clear();                // 开始第二条数据                values.put("name", "11 da vinvi code");                values.put("author", "11 brown");                values.put("pages", 222);                values.put("price", 111);                db.insert("Book", null, values);            }        });        // 改        Button updateData = (Button) findViewById(R.id.update_data);        updateData.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                SQLiteDatabase db = dbHelper.getWritableDatabase();                ContentValues values = new ContentValues();                values.put("name", "hahaha");                db.update("Book", values, "name = ?", new String[]{"The da vinvi code"});            }        });        // 删        Button deleteData = (Button) findViewById(R.id.delete_data);        deleteData.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                SQLiteDatabase db = dbHelper.getWritableDatabase();                db.delete("Book", "pages > ?", new String[]{"500"});            }        });        // 查        Button queryData = (Button) findViewById(R.id.query_data);        queryData.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                SQLiteDatabase db = dbHelper.getWritableDatabase();                Cursor cursor = db.query("Book", null , null, null, null, null, null);                if (cursor.moveToFirst()){                    do {                        // 遍历Cursor 取出数据并打印                        String name = cursor.getString(cursor.getColumnIndex("name"));                        Log.d("MainActivity", "书名是：" + name);                    } while (cursor.moveToNext());                }                cursor.close();            }        });    }}