Android(安卓)GreenDao数据库使用

一、先在项目中进行配置
1> 在项目的build的文件中添加，在dependencies里

classpath 'org.greenrobot:greendao-gradle-plugin:3.2.0'

2>在module里的配置
在最上面添加

 apply plugin: 'org.greenrobot.greendao'

3>在Android中添加

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 'dao的包名，包名默认是entity所在的包' （改成自己的dao包路径）        targetGenDir 'src/main/java'//生成数据库文件的目录（不用改）    }

4>添加依赖

implementation 'org.greenrobot:greendao:3.2.2'

二、创建数据库

@Entitypublic class DataDao {    @Id(autoincrement = true)//添加注解，自增    private Long id;    private String name;//数据库中的一些字段    private String sex;    private int age;}

写完这些以后，使用锤子锤一下，锤完后就会自动创建三个类

三、创建一个类继承Application

public class MyApp extends Application {    private static DaoSession daoSession;    @Override    public void onCreate() {        super.onCreate();        initGreenDao();    }    private void initGreenDao() {        DaoMaster.DevOpenHelper helper = new DaoMaster.DevOpenHelper(this, "Student");//上下文，数据库名        SQLiteDatabase writableDatabase = helper.getWritableDatabase();        DaoMaster master = new DaoMaster(writableDatabase);        daoSession = master.newSession();    }    public static DaoSession getDaoSession() {        return daoSession;    }}

记得要在清单文件中注册

四、Activity中的逻辑代码，简单的增删改查操作

public class MainActivity extends AppCompatActivity implements View.OnClickListener {    private Button send_insert;    private Button send_delete;    private Button send_update;    private Button send_select;    private TextView send_text;    private DataDaoDao dataDaoDao;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initView();        dataDaoDao = MyApp.getDaoSession().getDataDaoDao();    }    private void initView() {        send_insert = (Button) findViewById(R.id.send_insert);        send_delete = (Button) findViewById(R.id.send_delete);        send_update = (Button) findViewById(R.id.send_update);        send_select = (Button) findViewById(R.id.send_select);        send_text = (TextView) findViewById(R.id.send_text);        send_insert.setOnClickListener(this);        send_delete.setOnClickListener(this);        send_update.setOnClickListener(this);        send_select.setOnClickListener(this);    }    @Override    public void onClick(View v) {        switch (v.getId()) {            case R.id.send_insert:                insertSql();                break;            case R.id.send_delete:                deleteSql();                break;            case R.id.send_update:                updateSql();                break;            case R.id.send_select:                selectSql();                break;        }    }    //查询    private void selectSql() {        send_text.setText("");        List as = dataDaoDao.loadAll();//查询全部        send_text.setText(as.toString());    }    //修改    private void updateSql() {        DataDao load = dataDaoDao.load(1l);//根据id修改，因为id为long类型，所以是1l        load.setAge(66);        load.setName("李白");        load.setSex("男");        dataDaoDao.update(load);//修改    }    //删除    private void deleteSql() {        dataDaoDao.deleteByKey(1l);//删除同样是根据id        Toast.makeText(MainActivity.this, "删除成功", Toast.LENGTH_SHORT).show();    }    //添加    private void insertSql() {        DataDao a = new DataDao("杜甫", "男", 24);//添加时，先创建对象，写入参数，调用insert方法        long insert = dataDaoDao.insert(a);        if (insert > 0) {//当返回值大于0是，说明成功            Toast.makeText(MainActivity.this, "添加成功", Toast.LENGTH_SHORT).show();        }    }}

五、对应的xml布局文件

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