从另一个线程读取 RealmObject [英] Reading a RealmObject from another thread

问题描述

我有一个 RealmObject User，我将它存储在单例中并在整个应用程序中访问——它是在 UI 线程上检索的.该对象代表已登录的用户，并与 Item 类具有一对多关系.在事务中更改它时，例如:

I have a RealmObject User that I store in a singleton and access throughout the application -- it was retrieved on the UI thread. The object represents the logged in user, and has a one-to-many relationship with the Item class. When changing it in a transaction such as in:

RealmSingleton.getUserInstance().executeTransactionAsync(new Realm.Transaction() {
    @Override
    public void execute(Realm realm) {
        User user = realm.where(User.class).equalTo("mId",UserSingleton.getUser().getId()).findFirst();
        user.deleteItem(mItem.getClassId());
    }
});

这行不通，因为我正在另一个线程中发生的事务内部访问它.只是为了澄清一下，我在这里需要做的是将用户的 id 存储在事务之外，然后在进行查询时访问事务中存储的变量，就像这样?

This won't work because I'm accessing it inside of the transaction that occurs in another thread. Just to clarify, what I need to do here is store the user's id outside of the transaction and then access that stored variable within the transaction when making the query, like so?

Integer userId = UserSingleton.getUser().getId();
Integer classId = mItem.getClassId();
RealmSingleton.getUserInstance().executeTransactionAsync(new Realm.Transaction() {
        @Override
        public void execute(Realm realm) {
            User user = realm.where(User.class).equalTo("mId",userId).findFirst();
            user.deleteItem(classId);
        }
    });

推荐答案

是的，没错.您无法在多个线程上访问对象，因此在您的情况下，存储对 ID 的引用并使用它来重新查询对象是正确的方法.

Yes, that is correct. You cannot access an object on multiple threads, so in your case storing a reference to the ID and use that to requery the object is the right approach.

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