Right way of doing Realm Migration Android

Question

We use Realm for our app. Our app has been beta released. Now I want to add a field to one of our realm objects. So I got to write RealmMigration and I wrote one too. The Question here is how to apply this Realm migration to my app. I use Realm.getInstance() get the realm instance whenever I want to something. Remember, Realm.getInstance() is being used in the entire app everytime, I want to access Realm database.

So, I am bit Queried on how to apply this migration? Any leads can be helpful. Thanks.

My RealmMigration is as follows.

public class RealmMigrationClass implements RealmMigration {
    @Override
    public void migrate(DynamicRealm realm, long oldVersion, long newVersion) {
        if(oldVersion == 0) {
            RealmSchema sessionSchema = realm.getSchema();

            if(oldVersion == 0) {
                RealmObjectSchema sessionObjSchema = sessionSchema.get("Session");
                sessionObjSchema.addField("isSessionRecordingUploading", boolean.class, FieldAttribute.REQUIRED)
                        .transform(new RealmObjectSchema.Function() {
                            @Override
                            public void apply(DynamicRealmObject obj) {
                                obj.set("isSessionRecordingUploading", false);
                            }
                        });


                sessionObjSchema.setNullable("isSessionRecordingUploading",false);
                oldVersion++;
            }

        }
    }

}

public class Session extends RealmObject {

    @PrimaryKey
    private String id;
    @Required
    private Date date;
    private double latitude;
    private double longitude;
    private String location;
    private String note;
    private String appVersion;
    private String appType;
    private String deviceModel;
    private HeartRecording heart;
    private TemperatureRecording temperature;
    private LungsRecording lungs;
    @NotNull
    private boolean isSessionRecordingUploading;
    private boolean sessionInfoUploaded;
    private boolean lungsRecordingUploaded;
    private boolean heartRecordingUploaded;

}

Removed Getter and Setters from RealmObject to cut short the Question. The exception occurred when I try to reinstall the app without uninstalling the previous one. Please advice.

Answer 1

It is described here: https://realm.io/docs/java/latest/#migrations

But in essence, you just bump the schema version and set the configuration like this:

RealmConfiguration config = new RealmConfiguration.Builder(context)
    .schemaVersion(2) // Must be bumped when the schema changes
    .migration(new MyMigration()) // Migration to run
    .build();

Realm.setDefaultConfiguration(config);

// This will automatically trigger the migration if needed
Realm realm = Realm.getDefaultInstance();