greendao的使用

一.准备工作
在工程的build.gradle文件中添加

 repositories {
       ...
        mavenCentral()
    }
    dependencies {
        ...
        classpath 'org.greenrobot:greendao-gradle-plugin:3.3.0' 
    }

在项目的build.gradle文件中添加

apply plugin: 'org.greenrobot.greendao'

android {
    ...
    greendao {
        schemaVersion 1
    }
}

dependencies {
    ...
    implementation 'org.greenrobot:greendao:3.3.0'
}

（1）当Bean类对象发生改变时，schemaVersion的数值要增加。
（2）目前引用的版本是最新版，后续更新要注意上方的参考文档。
 

二. 创建实体类

例：

@Entity
public class TestUser {
    @Id(autoincrement = true)
    private Long id;
    @NotNull
    private String name;
    @NotNull
    private int age;
    @NotNull
    private String sex;
    @Index(unique = true)
    private String uid;
}
主键一定要大写的Long。
点击Build → Make Project会自动生成代码。

@Entity
public class TestUser {
    @Id(autoincrement = true)
    private Long id;
    @NotNull
    private String name;
    @NotNull
    private int age;
    @NotNull
    private String sex;
    @Index(unique = true)
    private String uid;
    @Generated(hash = 1872927493)
    public TestUser(Long id, @NotNull String name, int age, @NotNull String sex,
            String uid) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.sex = sex;
        this.uid = uid;
    }
    @Generated(hash = 925009630)
    public TestUser() {
    }
    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;
    }
    public int getAge() {
        return this.age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getSex() {
        return this.sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public String getUid() {
        return this.uid;
    }
    public void setUid(String uid) {
        this.uid = uid;
    }
}

三.初始化

可以将初始化以及增删改查进行封装，在初始化时需要context而且只需要初始化一次，为防止内存泄露所以我们将初始化放在Application进行操作。

public class DbController {
    /**
     * Helper
     */
    private DaoMaster.DevOpenHelper mHelper;//获取Helper对象
    /**
     * 数据库
     */
    private SQLiteDatabase db;
    /**
     * DaoMaster
     */
    private DaoMaster mDaoMaster;
    /**
     * DaoSession
     */
    private DaoSession mDaoSession;
    /**
     * 上下文
     */
    private Context context;
    /**
     * dao
     */
    private PersonInforDao personInforDao;

    private static DbController mDbController;

    /**
     * 获取单例
     */
    public static DbController getInstance(Context context){
        if(mDbController == null){
            synchronized (DbController.class){
                if(mDbController == null){
                    mDbController = new DbController(context);
                }
            }
        }
        return mDbController;
    }
    /**
     * 初始化
     * @param context
     */
    public DbController(Context context) {
        this.context = context;
        mHelper = new DaoMaster.DevOpenHelper(context,"person.db", null);
        mDaoMaster =new DaoMaster(getWritableDatabase());
        mDaoSession = mDaoMaster.newSession();
        personInforDao = mDaoSession.getPersonInforDao();
    }
    /**
     * 获取可读数据库
     */
    private SQLiteDatabase getReadableDatabase(){
        if(mHelper == null){
            mHelper = new DaoMaster.DevOpenHelper(context,"person.db",null);
        }
        SQLiteDatabase db =mHelper.getReadableDatabase();
        return db;
    }

    /**
     * 获取可写数据库
     * @return
     */
    private SQLiteDatabase getWritableDatabase(){
        if(mHelper == null){
            mHelper =new DaoMaster.DevOpenHelper(context,"person.db",null);
        }
        SQLiteDatabase db = mHelper.getWritableDatabase();
        return db;
    }

    /**
     * 会自动判定是插入还是替换
     * @param personInfor
     */
    public void insertOrReplace(PersonInfor personInfor){
        personInforDao.insertOrReplace(personInfor);
    }
    /**插入一条记录，表里面要没有与之相同的记录
     *
     * @param personInfor
     */
    public long insert(PersonInfor personInfor){
      return  personInforDao.insert(personInfor);
    }

    /**
     * 更新数据
     * @param personInfor
     */
    public void update(PersonInfor personInfor){
        PersonInfor mOldPersonInfor = personInforDao.queryBuilder().where(PersonInforDao.Properties.Id.eq(personInfor.getId())).build().unique();//拿到之前的记录
        if(mOldPersonInfor !=null){
            mOldPersonInfor.setName("张三");
            personInforDao.update(mOldPersonInfor);
        }
    }
    /**
     * 按条件查询数据
     */
    public List<PersonInfor> searchByWhere(String wherecluse){
        List<PersonInfor>personInfors = (List<PersonInfor>) personInforDao.queryBuilder().where(PersonInforDao.Properties.Name.eq(wherecluse)).build().unique();
        return personInfors;
    }
    /**
     * 查询所有数据
     */
    public List<PersonInfor> searchAll(){
        List<PersonInfor>personInfors=personInforDao.queryBuilder().list();
        return personInfors;
    }
    /**
     * 删除数据
     */
    public void delete(String wherecluse){
        personInforDao.queryBuilder().where(PersonInforDao.Properties.Name.eq(wherecluse)).buildDelete().executeDeleteWithoutDetachingEntities();
    }
}

看看我们的MainActivity

public class MainActivity extends AppCompatActivity {

    private Button Add,Delete,Update,Search;
    private DbController mDbController;
    private PersonInfor personInfor1,personInfor2,personInfor3,personInfor4;
    private long insertTipId;
    private TextView dataArea;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mDbController = DbController.getInstance(MainActivity.this);
        initView();
        Envent();
        similateData();
    }

    private void similateData() {
        personInfor1 = new PersonInfor(null,"001","王大宝","男");
        personInfor2 = new PersonInfor(null,"002","李晓丽","女");
        personInfor3 = new PersonInfor(null,"003","王麻麻","男");
        personInfor4 = new PersonInfor(null,"004","王大锤","女");
    }

    private void Envent() {

        Add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //Add
               mDbController.insertOrReplace(personInfor1);

               mDbController.insertOrReplace(personInfor2);

               mDbController.insertOrReplace(personInfor3);

               mDbController.insertOrReplace(personInfor4);

                showDataList();
            }
        });
        Delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //Delete
                mDbController.delete("王麻麻");

                showDataList();
            }
        });

        Update.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //Update
                mDbController.update(personInfor1);

                showDataList();
            }
        });

        Search.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //Search
                showDataList();
            }
        });
    }

    private void showDataList() {
        StringBuilder sb = new StringBuilder();
       List<PersonInfor>personInfors = mDbController.searchAll();
       for(PersonInfor personInfor:personInfors){
          // dataArea.setText("id:"+p);
           sb.append("id:").append(personInfor.getId())
             .append("perNo:").append(personInfor.getPerNo())
             .append("name:").append(personInfor.getName())
             .append("sex:").append(personInfor.getSex())
             .append("\n");
       }
       dataArea.setText(sb.toString());
    }

    private void initView() {

        Add = findViewById(R.id.Add);

        Delete = findViewById(R.id.Delete);

        Update = findViewById(R.id.Update);

        Search = findViewById(R.id.Search);

        dataArea= findViewById(R.id.tips);

    }
}