简单的写一个GreenDao

版权声明：本文为宠歆小王子的原创文章，未经宠歆小王子允许不得转载。 https://blog.csdn.net/qq_41698379/article/details/83626736

权限以及依赖

将下面注册到自己创建的应用的build.gradle里

apply plugin: 'org.greenrobot.greendao'

    implementation 'org.greenrobot:greendao:3.2.2'

将下面的添加到总工程里的build.gradle

jcenter()
mavenCentral()

classpath 'org.greenrobot:greendao-gradle-plugin:3.2.2'

person

@Entity(nameInDb = "person_table")
public class Person {

    @Id(autoincrement = true)
    public Long id;
    @Property(nameInDb = "name")
    public String mingzi;
    public int age;
    @Transient
    public String identity;

    @Generated(hash = 244725397)
    public Person(Long id, String mingzi, int age) {
        this.id = id;
        this.mingzi = mingzi;
        this.age = age;
    }

    @Generated(hash = 1024547259)
    public Person() {
    }
   
    @Override
    public String toString() {
        return "Person{" +
                "id=" + id +
                ", mingzi='" + mingzi + '\'' +
                ", age=" + age +
                ", identity='" + identity + '\'' +
                '}';
    }

    public Long getId() {
        return this.id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getMingzi() {
        return this.mingzi;
    }

    public void setMingzi(String mingzi) {
        this.mingzi = mingzi;
    }

    public int getAge() {
        return this.age;
    }

    public void setAge(int age) {
        this.age = age;
    }

}

MainActivity

public class MainActivity extends AppCompatActivity {

    private static final String TAG ="MainActivity" ;
    private DaoSession daoSession;
    private int index;
    private PersonDao personDao;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        daoSession = DaoManager.getInstance(this).getDaoSession();

        personDao =daoSession.getPersonDao();

    }

    public void query(View view){
        List<Person> list = personDao.queryBuilder()
                .where(PersonDao.Properties.Age.lt(500))
                .orderDesc(PersonDao.Properties.Age)
                .build()
                .list();
        for (Person person: list ) {
            Log.e(TAG, "query: "+person.toString() );

        }
    }

    public void add(View view){
        index++;
        Person person = new Person(null,"name" + index,index * 10);
        personDao.insert(person);
    }


    public void update(View view){
       List<Person> list = personDao.queryBuilder()
               .where(PersonDao.Properties.Age.lt(500))
               .orderDesc(PersonDao.Properties.Age)
               .build()
               .list();
        for (Person person: list) {
            if (person.age ==20){
                person.age = 100;
                personDao.update(person);
            }
        }
    }

    public void delete(View view){
        Person person = personDao.queryBuilder()
                .where(PersonDao.Properties.Id.eq(2))
                .build()
                .unique();

        if (person != null){
            personDao.delete(person);
        }

    }
}

DaoManager

public class DaoManager {
    private static DaoManager daoManager;
    private DaoSession daoSession;

        public DaoManager(Context context) {
            daoSession = DaoMaster.newDevSession(context,"person.db");
        }

        public static DaoManager getInstance(Context context){
            if (daoManager == null){
                synchronized (DaoManager.class){
                    if (null ==daoManager){
                        daoManager = new DaoManager(context);
                    }
                }
            }
            return daoManager;
        }

        public DaoSession getDaoSession(){
            return daoSession;
        }
}

xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.bwie.wang.myagreendao.MainActivity">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="query"
        android:text="query" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="add"
        android:text="add" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="update"
        android:text="update" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="delete"
        android:text="delete" />

</LinearLayout>