java 令人敬畏的境界 - MainActivity（2）

Posted 2021-05-08

package net.myanmarlinks.awesomerealm;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;

import net.myanmarlinks.awesomerealm.model.Author;
import net.myanmarlinks.awesomerealm.model.Category;
import net.myanmarlinks.awesomerealm.model.Post;

import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

import io.realm.Realm;

public class MainActivity extends AppCompatActivity {

    private Realm realm;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        realm = Realm.getDefaultInstance();

        List<Category> categories = new ArrayList<>();
        List<Author> authors = new ArrayList<>();

        categories.add(new Category(getUniqueID(), "News"));
        categories.add(new Category(getUniqueID(), "IT"));
        categories.add(new Category(getUniqueID(), "Breaking News"));

        authors.add(new Author(getUniqueID(), "Aung Aung"));
        authors.add(new Author(getUniqueID(), "Baung Baung"));
        authors.add(new Author(getUniqueID(), "Hla Hla"));

        realm.beginTransaction();
        realm.copyToRealm(categories);
        realm.copyToRealmOrUpdate(authors);
        realm.commitTransaction();

        Category category = realm.where(Category.class).equalTo("id", categories.get(0).getId()).findFirst();
        Author author = realm.where(Author.class).equalTo("id", authors.get(0).getId()).findFirst();


        realm.beginTransaction();
        Post post = realm.createObject(Post.class, getUniqueID());
        post.setTitle("Hello World");
        post.setCategory(category);
        post.setAuthor(author);
        realm.commitTransaction();

        List<Post> posts = realm.where(Post.class).equalTo("author.id", author.getId()).findAll();
        Log.d("POSTS", posts.get(0).getCategory().getName());
    }

    private String getUniqueID() {
        return UUID.randomUUID().toString();
    }


}