RealmMigrationNeededException 同时

Question

我有一个实时应用程序，它使用领域的早期版本（v0.85.1），我正在开发一个使用领域 4.2.0 版本的新版本，并且还进行了架构更改。架构更改只是添加到一个表中的一列。对于迁移我有这个课程。

public class ImRealmMigration implements RealmMigration{
    @Override
    public void migrate(DynamicRealm realm, long oldVersion, long newVersion) {

        RealmSchema schema = realm.getSchema();

        if(oldVersion == 0){
            schema.get("Layout")
                    .addField("orientation", String.class, FieldAttribute.REQUIRED);
            oldVersion++;
        }
    }
}

在应用程序类中我有这个

 Realm.init(this);
        RealmConfiguration realmConfiguration = new RealmConfiguration.Builder()
                .name("default.realm")
                .schemaVersion(1)
                .migration(new ImRealmMigration())
                .build();
        Realm.setDefaultConfiguration(realmConfiguration); // Make this Realm the default

        Realm realm = Realm.getInstance(realmConfiguration);

当我运行该应用程序时，它会一直工作到最后一行，抛出 RealmMigrationNeededException 并继续列出架构中的所有主键，表示它们已变为可选。有谁知道为什么会发生这种情况以及我能做些什么来解决它？这是堆栈跟踪：

                FATAL EXCEPTION: main  
                    java.lang.RuntimeException: 
                Unable to start activity io.realm.exceptions.RealmMigrationNeededException: 

        Migration is required due to the following errors:

- Property 'Book.privateId' has been made optional.
                                                                                                       - Property 'BookType.bookTypeId' has been made optional.
                                                                                                       - Property 'Cart.id' has been made optional.
                                                                                                       - Property 'ClipArt.url' has been made optional.
                                                                                                       - Property 'Contact.userId' has been made optional.
                                                                                                       - Property 'CreditAccount.id' has been made optional.
                                                                                                       - Property 'Layout.layoutId' has been made optional.
                                                                                                       - Property 'LayoutClipArtItem.layoutItemId' has been made optional.
                                                                                                       - Property 'LayoutItem.itemId' has been made optional.
                                                                                                       - Property 'LayoutPhotoItem.layoutItemId' has been made optional.
                                                                                                       - Property 'LayoutShapeItem.layoutItemId' has been made optional.
                                                                                                       - Property 'LayoutTextItem.layoutItemId' has been made optional.
                                                                                                       - Property 'OrderSession.id' has been made optional.
                                                                                                       - Property 'PagePhoto.pagePhotoId' has been made optional.
                                                                                                       - Property 'Photo.privateId' has been made optional.
                                                                                                       - Property 'PhotoOrigin.identifier' has been made optional.
                                                                                                       - Property 'PrintPack.privateId' has been made optional.
                                                                                                       - Property 'PrintType.printTypeId' has been made optional.
                                                                                                       - Property 'Product.productId' has been made optional.
                                                                                                       - Property 'ProductFamilyMarketing.productFamilyType' has been made optional.
                                                                                                       - Property 'Region.rid' has been made optional.
                                                                                                           at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3151)
                                                                                                           at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3261)
                                                                                                           at android.app.ActivityThread.access$1000(ActivityThread.java:219)
                                                                                                           at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1735)
                                                                                                           at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                                           at android.os.Looper.loop(Looper.java:145)
                                                                                                           at android.app.ActivityThread.main(ActivityThread.java:6939)
                                                                                                           at java.lang.reflect.Method.invoke(Native Method)
                                                                                                           at java.lang.reflect.Method.invoke(Method.java:372)
                                                                                                           at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
                                                                                                           at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
                                                                                                        Caused by: io.realm.exceptions.RealmMigrationNeededException: Migration is required due to the following errors:
                                                                                                       - Property 'Book.privateId' has been made optional.
                                                                                                       - Property 'BookType.bookTypeId' has been made optional.
                                                                                                       - Property 'Cart.id' has been made optional.
                                                                                                       - Property 'ClipArt.url' has been made optional.
                                                                                                       - Property 'Contact.userId' has been made optional.
                                                                                                       - Property 'CreditAccount.id' has been made optional.
                                                                                                       - Property 'Layout.layoutId' has been made optional.
                                                                                                       - Property 'LayoutClipArtItem.layoutItemId' has been made optional.
                                                                                                       - Property 'LayoutItem.itemId' has been made optional.
                                                                                                       - Property 'LayoutPhotoItem.layoutItemId' has been made optional.
                                                                                                       - Property 'LayoutShapeItem.layoutItemId' has been made optional.
                                                                                                       - Property 'LayoutTextItem.layoutItemId' has been made optional.
                                                                                                       - Property 'OrderSession.id' has been made optional.
                                                                                                       - Property 'PagePhoto.pagePhotoId' has been made optional.
                                                                                                       - Property 'Photo.privateId' has been made optional.
                                                                                                       - Property 'PhotoOrigin.identifier' has been made optional.
                                                                                                       - Property 'PrintPack.privateId' has been made optional.
                                                                                                       - Property 'PrintType.printTypeId' has been made optional.
                                                                                                       - Property 'Product.productId' has been made optional.
                                                                                                       - Property 'ProductFamilyMarketing.productFamilyType' has been made optional.
                                                                                                       - Property 'Region.rid' has been made optional.
                                                                                                           at io.realm.internal.OsSharedRealm.nativeGetSharedRealm(Native Method)
                                                                                                           at io.realm.internal.OsSharedRealm.<init>(OsSharedRealm.java:172)
                                                                                                           at io.realm.internal.OsSharedRealm.getInstance(OsSharedRealm.java:219)
                                                                                                           at io.realm.BaseRealm.<init>(BaseRealm.java:124)
                                                                                                           at io.realm.BaseRealm.<init>(BaseRealm.java:93)
                                                                                                           at io.realm.Realm.<init>(Realm.java:153)
                                                                                                           at io.realm.Realm.createInstance(Realm.java:424)
                                                                                                           at io.realm.RealmCache.doCreateRealmOrGetFromCache(RealmCache.java:342)
                                                                                                        at io

Answer 1

0.89.0

重大变化

对于 String、Byte、Short、Integer 和 Long 类型，@PrimaryKey 字段值现在可以为 null。应使用 RealmObjectSchema.setNullable() 或添加 @Required 注释来迁移较旧的 Realms (#2515)。

请参阅版本0.89.0的更改日志

您可以通过添加字段来轻松绕过此@Required问题@PrimaryKey。