【Android】Room的使用简示

蔚落 2022-09-17 06:18 197阅读 0赞

### Room的使用简示 ###

*  database
 *  daos
 *  managers
 *  mos

**依赖**

implementation "android.arch.persistence.room:runtime:1.1.1"
    annotationProcessor "android.arch.persistence.room:compiler:1.1.1"

> Crazy Coding

# database #

`LocalDataBase`

@Database(
            version = 1,
            exportSchema = false,
            entities = {DbPerson.class}
    )
    public abstract class LocalDataBase extends RoomDatabase {
        public abstract DbPersonDao dbPersonDao();
    }

# daos #

`DbPersonDao`

@Dao
    public interface DbPersonDao {
        @Insert(onConflict = OnConflictStrategy.REPLACE)
        long[] insert(List<DbPerson> persons);
    
        @Insert(onConflict = OnConflictStrategy.REPLACE)
        long insert(DbPerson person);
    
        @Delete
        void delete(List<DbPerson> passPersonList);
    
        @Delete
        void delete(DbPerson person);
    
        @Query("DELETE From Person")
        void deleteAll();
    
        @Update
        void update(DbPerson person);
    
        @Query("SELECT * From Person Where person_uuid = :uuid")
        DbPerson selectDbPersonByPersonUuid(String uuid);
    
        @Query("SELECT * From Person")
        List<DbPerson> selectDbPersonAll();
    
    }

# managers #

`DbManager`

public class DbManager {
    
        private static volatile LocalDataBase db;
    
        //创建database实例
        public static LocalDataBase init(Context context) {
            if (db == null) {
                //Room和SQLCipher的桥梁
                synchronized (LocalDataBase.class) {
                    if (db == null) {
                        //SafeHelperFactory factory = new SafeHelperFactory(KeyManager.getKey().toCharArray());
                        db = Room.databaseBuilder(
                                context.getApplicationContext(),
                                LocalDataBase.class, "local_db.db"
                        )
                                /*.addMigrations(MIGRATION_1_2)*///迁移升级
                                //.openHelperFactory(factory) //打开加密
                                //添加下面这一行
                                //.fallbackToDestructiveMigration()
                                .build();
                    }
                }
            }
            return db;
        }
    
        /*val MIGRATION_1_2: Migration = object : Migration(1, 2) {
            override fun migrate(database: SupportSQLiteDatabase) {
                database.execSQL("ALTER TABLE 'PassPerson' ADD COLUMN 'person_card_no' VARCHAR(20) DEFAULT ''")
            }
        }*/
    
        public static LocalDataBase getDatabase() {
            return db;
        }
    
        //获取唯一id
        public static long getUniqueId() {
            return System.nanoTime() << 10;
        }
    
        //获取唯一字符串
        public static String getUniqueString() {
            return UUID.randomUUID().toString().replace("-", "");
        }
    }

`DbPersonManager`

public class DbPersonManager {
        private static DbPersonDao dbPersonDao() {
            return DbManager.getDatabase().dbPersonDao();
        }
    
        /*static insert(dbPersons List<DbPerson>) LongArray {
            return dbPersonDao().insert(dbPersons)
        }*/
    
        public static Long insert(DbPerson dbPerson) {
            return dbPersonDao().insert(dbPerson);
        }
    
        public static void update(DbPerson dbPerson) {
            dbPersonDao().update(dbPerson);
        }
    
        public static void delete(DbPerson dbPerson) {
            dbPersonDao().delete(dbPerson);
        }
    
        public static void delete(List<DbPerson> dbPersonList) {
            dbPersonDao().delete(dbPersonList);
        }
    
        public static void deleteAll() {
            dbPersonDao().deleteAll();
        }
    
        public static DbPerson selectDbPersonByPersonUuid(String uuid) {
            return dbPersonDao().selectDbPersonByPersonUuid(uuid);
        }
    
        public static List<DbPerson> selectDbPersonAll() {
            return dbPersonDao().selectDbPersonAll();
        }
    }

# mos #

@Entity(tableName = "Person")
    public class DbPerson {
        @NonNull
        @PrimaryKey
        @ColumnInfo(name = "person_uuid")
        private String personUuid;
    
        @ColumnInfo(name = "person_attribute")
        private String personAttribute;
    
        @ColumnInfo(name = "person_image")
        private String personImage;
    
        @ColumnInfo(name = "feature_status")
        private int featureStatus;
    
        public DbPerson(String personUuid, String personAttribute, String personImage, int featureStatus) {
            this.personUuid = personUuid;
            this.personAttribute = personAttribute;
            this.personImage = personImage;
            this.featureStatus = featureStatus;
        }
    
        public String getPersonUuid() {
            return personUuid;
        }
    
        public void setPersonUuid(String personUuid) {
            this.personUuid = personUuid;
        }
    
        public String getPersonAttribute() {
            return personAttribute;
        }
    
        public void setPersonAttribute(String personAttribute) {
            this.personAttribute = personAttribute;
        }
    
        public String getPersonImage() {
            return personImage;
        }
    
        public void setPersonImage(String personImage) {
            this.personImage = personImage;
        }
    
        public int getFeatureStatus() {
            return featureStatus;
        }
    
        public void setFeatureStatus(int featureStatus) {
            this.featureStatus = featureStatus;
        }
    
        @Override
        public String toString() {
            return "DbPerson{" +
                    "personUuid='" + personUuid + '\'' +
                    ", personAttribute='" + personAttribute + '\'' +
                    ", personImage='" + personImage + '\'' +
                    ", featureStatus=" + featureStatus +
                    '}';
        }
    }

> How To Use

*  初始化

public class MainApplication extends MultiDexApplication {
    
        @Override
        public void onCreate() {
            super.onCreate();
            ...
            DbManager.init(this);
        }
        ...
    }

*  调用方法

DbPersonManager.insert(dbPerson)