《Android开源库》 Realm For Android~ Scheme & JSON & Notification（译文）

// Create the module
@RealmModule(classes = { Person.class, Dog.class })
public class MyModule {
}

// Set the module in the RealmConfiguration to allow only classes defined by the module.
RealmConfiguration config = new RealmConfiguration.Builder()
  .modules(new MyModule())
  .build();

// It is possible to combine multiple modules to one schema.
RealmConfiguration config = new RealmConfiguration.Builder()
  .modules(new MyModule(), new MyOtherModule())
  .build();

// Library must create a module and set library = true. This will prevent the default
// module from being created.
// allClasses = true can be used instead of listing all classes in the library.
@RealmModule(library = true, allClasses = true)
public class MyLibraryModule {
}

// Library projects are therefore required to explicitly set their own module.
RealmConfiguration libraryConfig = new RealmConfiguration.Builder()
  .name("library.realm")
  .modules(new MyLibraryModule())
  .build();

// Apps can add the library RealmModule to their own schema.
RealmConfiguration config = new RealmConfiguration.Builder()
  .name("app.realm")
  .modules(Realm.getDefaultModule(), new MyLibraryModule())
  .build();

// A RealmObject that represents a city
public class City extends RealmObject {
    private String city;
    private int id;
    // getters and setters left out ...
}

// Insert from a string
realm.executeTransaction(new Realm.Transaction() {
    @Override
    public void execute(Realm realm) {
        realm.createObjectFromJson(City.class, "{ city: \"Copenhagen\", id: 1 }");
    }
});

// Insert multiple items using an InputStream
realm.executeTransaction(new Realm.Transaction() {
    @Override
    public void execute(Realm realm) {
        try {
            InputStream is = new FileInputStream(new File("path_to_file"));
            realm.createAllFromJson(City.class, is);
        } catch (IOException e) {
            throw new RuntimeException();
        }
    }
});

public class MyActivity extends Activity {
    private Realm realm;
    private RealmChangeListener realmListener;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      realm = Realm.getDefaultInstance();
      realmListener = new RealmChangeListener() {
        @Override
        public void onChange(Realm realm) {
            // ... do something with the updates (UI, etc.) ...
        }};
      realm.addChangeListener(realmListener);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        // Remove the listener.
        realm.removeChangeListener(realmListener);
        // Close the Realm instance.
        realm.close();
    }
}

public class MyActivity extends Activity {
    private Realm realm;
    private RealmChangeListener puppiesListener;
    private RealmChangeListener dogListener;

    private RealmResults<Dog> puppies;
    private Dog dog;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      realm = Realm.getDefaultInstance();
      puppiesListener = new RealmChangeListener() {
        @Override
        public void onChange(RealmResults<Dog> puppies) {
            // ... do something with the updated puppies instance
        }};

      // Find all the puppies
      puppies = realm.where(Dog.class).lessThanOrEqualTo("age", 2).findAll();
      puppies.addChangeListener(puppiesListener);

      dogListener = new RealmChangeListener() {
        @Override
        public void onChange(Dog dog) {
            // ... do something with the updated Dog instance
        }};

      dog = realm.where(Dog.class).equalTo("name", "Fido").findFirst();
      dog.addChangeListener(dogListener);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        // Remove the listeners
        puppies.removeChangeListener(puppiesListener);
        dog.removeChangeListener(dogListener);
        // Close the Realm instance.
        realm.close();
    }
}

realm.removeAllChangeListeners();

Person person = realm.where(Person.class).findFirst();
person.getDogs(); // => 2 - Assume there are 2 dogs in the list
person.addChangeListener(new RealmChangeListener() {
                             @Override
                             public void onChange(Person person) {
                                 // React to the change in the Person instance.
                                 // This will also get called when any referenced dogs are updated.
                             }
                         });
Dog dog = person.getDogs().get(0);
realm.beginTransaction();
dog.setAge(5);
realm.commitTransaction();
// Person change listener is called on the next iteration of the run loop because
// a referenced dog object changed.

public class Dog extends RealmObject {
  public String name;
  public int age;
}

public class Person exteds RealmObject {
  public String name;
  public RealmList<Dog> dogs;
}

private final OrderedRealmCollectionChangeListener<RealmResults<Person>> changeListener = new OrderedRealmCollectionChangeListener() {
    @Override
    public void onChange(RealmResults<Person> collection, OrderedCollectionChangeSet changeSet) {
        // `null`  means the async query returns the first time.
        if (changeSet == null) {
            notifyDataSetChanged();
            return;
        }
        // For deletions, the adapter has to be notified in reverse order.
        OrderedCollectionChangeSet.Range[] deletions = changeSet.getDeletionRanges();
        for (int i = deletions.length - 1; i >= 0; i--) {
            OrderedCollectionChangeSet.Range range = deletions[i];
            notifyItemRangeRemoved(range.startIndex, range.length);
        }

        OrderedCollectionChangeSet.Range[] insertions = changeSet.getInsertionRanges();
        for (OrderedCollectionChangeSet.Range range : insertions) {
            notifyItemRangeInserted(range.startIndex, range.length);
        }

        OrderedCollectionChangeSet.Range[] modifications = changeSet.getChangeRanges();
        for (OrderedCollectionChangeSet.Range range : modifications) {
            notifyItemRangeChanged(range.startIndex, range.length);
        }
    }
};