安卓 GreenDao 基本使用

╰+哭是因爲堅強的太久メ 2021-09-26 03:08 427阅读 0赞

转载自:[http://blog.csdn.net/fengltxx/article/details/53708769][http_blog.csdn.net_fengltxx_article_details_53708769]  
第一步:将GreenDao引入到项目中(以Studio为例)

*  1.在Project–>budld.gradle中配置如下:

dependencies {
                classpath 'com.android.tools.build:gradle:2.0.0'
                // 这是需要配置的地方
                classpath 'org.greenrobot:greendao-gradle-plugin:3.2.1'//GreenDao
            }

*  2.在Modle–>build.gradle中配置:  
    \` apply plugin: ‘com.android.application’  
    // 这是需要配置的地方—1  
    apply plugin: ‘org.greenrobot.greendao’//GreenDao
    
        android {
            compileSdkVersion 23
            buildToolsVersion "23.0.3"
        
         ...
        }
        // 需要配置的地方-----2
        greendao {
            schemaVersion 1    // 当前数据库结构的版本
            //daoPackage 'com.greendao.gen' // 生成的DAO，DaoMaster和DaoSession的包名。默认是实体的包名。
            //targetGenDir 'src/main/java'  //生成源文件的路径。默认源文件目录是在build目录中的(build/generated/source/greendao)。
           // targetGenDirTest      //生成的单元测试的根目录。
        }
        
        dependencies {
            compile fileTree(dir: 'libs', include: ['*.jar'])
            testCompile 'junit:junit:4.12'
            compile 'com.android.support:appcompat-v7:23.4.0'
        
            // 需要配置的地方 -----3    GreenDao
            compile 'org.greenrobot:greendao:3.2.0'//GreenDao
            compile'org.greenrobot:greendao-generator:3.0.0'
        
        
        }`
 *  配置完成后,同步工程就可以了.  
    第二步:编写实体类

School类:

@Entity
        public class School { 
            @Id
            private Long id;
            private String name;
        }

*  编写完这个普通的实体类后.

点击导航栏上的Build–>Make Project.  
随后会看到这个实体类变身了. 如下:

/** * ONE Goal,ONE Passion! * Created by ${PK_Night} on 2016/12/12. * comment: */
        @Entity
        public class School { 
            @Id
            private Long id;
            private String name;
            @Transient
            private int tempUsageCount; // not persisted
            @Generated(hash = 2095953704)
            public School(Long id, String name) {
                this.id = id;
                this.name = name;
            }
            @Generated(hash = 1579966795)
            public School() {
            }
            public Long getId() {
                return this.id;
            }
            public void setId(Long id) {
                this.id = id;
            }
            public String getName() {
                return this.name;
            }
            public void setName(String name) {
                this.name = name;
            }
        }

帮我们生成了部分代码.

*注:生成代码后,不要在更改这个文件*

而且GreenDao已经帮我们生成了DAO等.DAO位置如下  
![这里写图片描述][SouthEast]

*  第三步:开始增删CRUD

第一种:使用SqliteOpenHelper对象去操作.

DaoMaster.DevOpenHelper helper = new DaoMaster.DevOpenHelper(this, "mydb", null);
                SQLiteDatabase db = helper.getWritableDatabase();
                // 原生sql 语句
                // String sql = "insert into school values(3,'txx')";
                // db.execSQL(sql); // 可执行曾,删,改 
              //db.rawQuery(); 执行查询

既然拿到了SQLiteDatabase对象,就可以直接使用sql操作了.如果你觉得GreenDao仅仅让我们方便地拿到 SQLiteDatabase那就太小看它了.它也可以像hibernate一样,直接操作对象来进行CRUD.

*  第二种: 使用DaoSession 直接根据对象进行CRUD.

DaoMaster.DevOpenHelper helper = new DaoMaster.DevOpenHelper(this, "mydb2", null);
             SQLiteDatabase db = helper.getWritableDatabase();
             DaoMaster daoMaster = new DaoMaster(db);
             DaoSession session = daoMaster.newSession();

*  增:  
    `school = new School((long)1,"fy"); session.insert(school);`
 *  删:

school = new School((long)1,"fy");
         session.delete(school);

*  改:

school = new School((long) 1, "fynight");
             session.update(school);

*  查:

//  条件查询
            List<School> schools = session.queryRaw(School.class, "where name = ?", new String[]{
       "fy"});
                    for (int i = 0; i < schools.size(); i++) { 
                        System.out.println("查询出来数据" + schools.get(i).getName());
                    }
    
            // 查询所有
             List<School> school = session.loadAll(School.class);
            String schoolName = "";
            for (int i = 0; i < school.size(); i++) { 
                schoolName += school.get(i).getName() + ",";
                System.out.println("查询出来数据" + schoolName);
            }

*简单的GreenDao简单demo已经 OK!接下来说一说 实体类注解*

[http_blog.csdn.net_fengltxx_article_details_53708769]: http://blog.csdn.net/fengltxx/article/details/53708769
[SouthEast]: /images/20210923/60623905f78f49f188a4e6076f8b3fef.png