android数据库框架LitePal的简单使用

迷南。 2022-07-14 06:55 225阅读 0赞

GitHub地址：https://github.com/LitePalFramework/LitePal

步骤1：下载

compile 'org.litepal.android:core:1.4.0'

步骤2：

配置文件litepal.xml 在 assets 文件夹

<?xml version="1.0" encoding="utf-8"?>
    <litepal>
        <dbname value="demo" ></dbname> 
    
        
        <version value="1" ></version>
    
        
        <list>
        </list>
    
        
    
    </litepal>

步骤3：配置LitePalApplication

或者自己重写的的Application

#### <manifest> <application android:name="com.example.MyOwnApplication" ... > ... </application> </manifest>      ####

public class MyOwnApplication extends AnotherApplication {
    
        @Override
        public void onCreate() {
            super.onCreate();
            LitePal.initialize(this);
        }
        ...
    }

使用：

1、创建表

public class Album extends DataSupport {
    
        @Column(unique = true, defaultValue = "unknown")
        private String name;
    
        private float price;
    
        private byte[] cover;
    
        private List<Song> songs = new ArrayList<Song>();
    
        // generated getters and setters.
        ...
    }

public class Song extends DataSupport {
    
        @Column(nullable = false)
        private String name;
    
        private int duration;
    
        @Column(ignore = true)
        private String uselessField;
    
        private Album album;
    
        // generated getters and setters.
        ...
    }

在litepal.xml 添加映射

2、获取数据库 必须使用否则报空错误 放在application或第一个启动的activity中都可以

SQLiteDatabase db = LitePal.getDatabase();

3、更新表 只需要修改Model

public class Album extends DataSupport {
    
        @Column(unique = true, defaultValue = "unknown")
        private String name;
    
        @Column(ignore = true)
        private float price;
    
        private byte[] cover;
    
        private Date releaseDate;
    
        private List<Song> songs = new ArrayList<Song>();
    
        // generated getters and setters.
        ...
    }

更新表后，然后增加litepal.xml中的版本号：

3、保存数据

Album album = new Album();
    album.setName("album");
    album.setPrice(10.99f);
    album.setCover(getCoverImageBytes());
    album.save();
    Song song1 = new Song();
    song1.setName("song1");
    song1.setDuration(320);
    song1.setAlbum(album);
    song1.save();
    Song song2 = new Song();
    song2.setName("song2");
    song2.setDuration(356);
    song2.setAlbum(album);
    song2.save();

4、更新数据

Album albumToUpdate = DataSupport.find(Album.class, 1);
    albumToUpdate.setPrice(20.99f); // raise the price
    albumToUpdate.save();

具体的id更新

Album albumToUpdate = new Album();
    albumToUpdate.setPrice(20.99f); // raise the price
    albumToUpdate.update(id);

使用条件更新多条

Album albumToUpdate = new Album();
    albumToUpdate.setPrice(20.99f); // raise the price
    albumToUpdate.updateAll("name = ?", "album");

5、删除数据

DataSupport.delete(Song.class, id);

删除全部

DataSupport.deleteAll(Song.class, "duration > ?" , "350");

6、查询数据

通过id查询1条数据