java - 迁移时如何删除Realm？

Question

这就是我想要的:

public class CustomRealmMigration implements RealmMigration {
    // Current version
    private static final long SCHEMA_VERSION = 4;

    private final Context mContext;

    public CustomRealmMigration(Context context) {
        mContext = context;
    }

    @Override
    public long execute(Realm realm, long version) {
        if (SCHEMA_VERSION < version) {
            // Rollback, not allow
            deleteRealm();
            return SCHEMA_VERSION;
        }
        return version;
    }

    private void deleteRealm() {
        RealmConfiguration realmConfiguration = new RealmConfiguration.Builder(mContext)
                .name(Realm.DEFAULT_REALM_NAME)
                .build();
        Realm.deleteRealm(realmConfiguration);
    }
}

有错误:

Caused by: java.lang.IllegalStateException: It's not allowed to delete the file associated with an open Realm. Remember to close() all the instances of the Realm before deleting its file.

迁移时如何删除Realm？或者如何在其他地方获取旧版本的 Realm？

Answer 1

如果您不想在架构更改时迁移数据，而只是重置/清除数据库，那么您可以执行以下操作:

RealmConfiguration realmConfiguration = new RealmConfiguration.Builder(mContext)
                .name(Realm.DEFAULT_REALM_NAME)
                .deleteRealmIfMigrationRequired()
                .build();

这也意味着您不必提供任何迁移代码。