GreenDao的配置以及简单实现增删改查

配置GreenDao

1.在项目的build.grade文件里加入一行代码
classpath 'org.greenrobot:greendao-gradle-plugin:3.2.0'

2.在app的build.grade里面加上代码
apply plugin: 'org.greenrobot.greendao'

3.在app的build.grad里面Android{}里加上代码

 greendao{
 schemaVersion 1 //指定数据库schema版本号，迁移等操作会用到
 //包名是活的这是变动的
  daoPackage 'soexample.umeng.com.greendaodemo.mydao' //dao的包名，包名默认是entity所在的包；
 targetGenDir 'src/main/java'//生成数据库文件的目录
  }

4.导入依赖
需要新建一个实体类 通过@Entity
通过锤子（make Project）
1:DaoMaster
2:DaoSession
3:StudentDao

GreenDao代码:

在App中新建数据库 在MainActivity中调用,一定要早AndroidManifest.xml中注册!

public class MyApp extends Application {

    private static DaoSession daoSession;

    @Override
    public void onCreate() {
        super.onCreate();
        initGreenDao();
    }

    private void initGreenDao() {
        //创建OpenHelper类
        DaoMaster.DevOpenHelper openHelper = new DaoMaster.DevOpenHelper(this, "user.db");
        //开启一个可写的数据库类
        SQLiteDatabase writableDatabase = openHelper.getWritableDatabase();
        //通过DaoMaster封装
        DaoMaster master = new DaoMaster(writableDatabase);
        daoSession = master.newSession();
    }

    public static DaoSession getDaoSession() {
        return daoSession;
    }
}

在MainActivity中的具体使用

 public class MainActivity extends AppCompatActivity {

    @BindView(R.id.insert)
    Button insert;
    @BindView(R.id.delete)
    Button delete;
    @BindView(R.id.update)
    Button update;
    @BindView(R.id.select)
    Button select;
    @BindView(R.id.Get_Content)
    TextView GetContent;
    private StudentDao studentDao;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
        studentDao = MyApp.getDaoSession().getStudentDao();

    }

    @OnClick({R.id.insert, R.id.delete, R.id.update, R.id.select})
    public void onViewClicked(View view) {
        switch (view.getId()) {
            case R.id.insert:
                insertData();
                break;
            case R.id.delete:
                deleteData();
                break;
            case R.id.update:
                updateData();
                break;
            case R.id.select:
                selectData();
                break;
        }
    }

    private void updateData() {
        Student student = studentDao.load(3l);
        student.setAge(18);
        student.setSex("美");
        studentDao.update(student);
        Toast.makeText(this, "修改成功", Toast.LENGTH_SHORT).show();
    }

    private void deleteData() {
        studentDao.deleteByKey(2l);
        Toast.makeText(this, "删除成功", Toast.LENGTH_SHORT).show();
    }

    private void selectData() {
        GetContent.setText("");
        List<Student> students = studentDao.loadAll();
        GetContent.setText(students.toString());
    }

    private void insertData() {
        Student student = new Student("哈哈哈", "帅", 3);
        long insert = studentDao.insert(student);
        if (insert > 0) {
            Toast.makeText(this, "插入成功", Toast.LENGTH_SHORT).show();
        }
    }
}

运行效果:

image.png