Realm : getTable() delete all then copyToRealm

Question

我有这段代码，它的目标是删除所有配方对象，删除此类对象后，我将使用列表中的新配方再次填充表格。

realm.beginTransaction();
realm.getTable(Recipe.class).clear();
realm.copyToRealm(list);
realm.commitTransaction();

这段代码的问题在于它抛出了这个异常

Value already exists: 18
io.realm.exceptions.RealmPrimaryKeyConstraintException: Value already exists: 18
    at io.realm.internal.Table.throwDuplicatePrimaryKeyException(Table.java:636)
    at io.realm.internal.Table.addEmptyRowWithPrimaryKey(Table.java:408)
    at io.realm.Realm.createObject(Realm.java:678)
    at io.realm.IngredientTypeRealmProxy.copy(IngredientTypeRealmProxy.java:300)
    at io.realm.IngredientTypeRealmProxy.copyOrUpdate(IngredientTypeRealmProxy.java:295)     at io.realm.IngredientRealmProxy.copy(IngredientRealmProxy.java:470)
    at io.realm.IngredientRealmProxy.copyOrUpdate(IngredientRealmProxy.java:451)
    at io.realm.DefaultRealmModuleMediator.copyOrUpdate(DefaultRealmModuleMediator.java:208)
    at io.realm.Realm.copyOrUpdate(Realm.java:1166)
    at io.realm.Realm.copyToRealm(Realm.java:697)
    at io.realm.Realm.copyToRealm(Realm.java:735)
    at team.jcandfriends.namnam.ui.HardRefreshActivity$1.onNext(HardRefreshActivity.java:152)
    at rx.observers.SafeSubscriber.onNext(SafeSubscriber.java:139)
    at rx.internal.operators.OperatorObserveOn$ObserveOnSubscriber.pollQueue(OperatorObserveOn.java:202)
    at rx.internal.operators.OperatorObserveOn$ObserveOnSubscriber$2.call(OperatorObserveOn.java:162)
    at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:135)
    at android.app.ActivityThread.main(ActivityThread.java:5294)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)

我的问题是为什么首先发生这种情况，我首先使用 realm.getTable(Recipe.class).clear() 删除了所有对象，所以我假设使用realm.copyToRealm(list)已经是安全的，因为表已经是空的。我很抱歉我的无知，我喜欢领域，就像真的:)

我从这里获取数据：https://namnamnam.herokuapp.com/api/recipes

Answer 1

你应该试试这个

realm.executeTransaction(new Realm.Transaction() {
    @Override
    public void execute(Realm realm) {
        realm.where(Recipe.class).findAll().deleteAllFromRealm();
        realm.insertOrUpdate(list);
    }
});