Realm.io - 如何更新对象？

Question

我正在使用 0.81.1 版本的 Realm。我有这个 class:

public class KanjiComp extends RealmObject {

    @PrimaryKey
    private String character;
    private String strokes;
    private int frequency;

    public String getCharacter() {
        return character;
    }

    public void setCharacter(String character) {
        this.character = character;
    }

    public String getStrokes() {
        return strokes;
    }

    public void setStrokes(String strokes) {
        this.strokes = strokes;
    }

    public int getFrequency() {
        return frequency;
    }

    public void setFrequency(int frequency) {
        this.frequency = frequency;
    }
}

我第一次这样创建对象：

    KanjiComp realmKanjiComp = realm.createObject(KanjiComp.class);
    realmKanjiComp.setCharacter(cur.getString(cur.getColumnIndex("literal")));
    realmKanjiComp.setStrokes(cur.getString(cur.getColumnIndex("strokes")));
    realmKanjiComp.setFrequency(0);

我想增加频率值。为此，我需要帮助我更新频率的方法。

Realm 文档是这样说的：

Using primary keys makes it possible to use the createOrUpdate() method, which will look for an existing object with this primary key, an update it if it finds one; if none are found, it will create a new object instead.

但我找不到 createOrUpdate() 方法。使用 JSON 的所有方法。

我的完整代码如下所示：

        try {
            KanjiComp realmKanjiComp = realm.createObject(KanjiComp.class);
            character = cur.getString(cur.getColumnIndex("literal"));
            realmKanjiComp.setCharacter(cur.getString(cur.getColumnIndex("literal")));
            realmKanjiComp.setStrokes(cur.getString(cur.getColumnIndex("strokes")));
            realmKanjiComp.setFrequency(0);
        } catch (Exception e) {
            RealmQuery<KanjiComp> query = realm.where(KanjiComp.class);
            query.equalTo("character", character);
            RealmResults<KanjiComp> rKanjiComp = query.findAll();
            KanjiComp oldKanjiComp = rKanjiComp.get(0);

            KanjiComp realmKanjiComp = realm.update(KanjiComp.class);//update is underlined
            realmKanjiComp.setCharacter(cur.getString(cur.getColumnIndex("literal")));
            realmKanjiComp.setStrokes(cur.getString(cur.getColumnIndex("strokes")));
            realmKanjiComp.setFrequency(oldKanjiComp.getFrequency()+1);
        }

所以我的问题是，如何更新对象的值？有什么方法可以增加我的对象的价值吗？

Answer 1

我会选择这样的东西：

void createKanjiCompOrUpdateFrequency() {
    // This query is fast because "character" is an indexed field
    KanjiComp kanjoComp = realm.where(KanjiComp.class)
                               .equalTo("character", someValue)
                               .findFirst();
    realm.beginTransaction();
    if (kanjiComp == null) {
        KanjiComp kanjiComp = realm.createObject(KanjiComp.class);
        // set the fields here
    } else {
        kanjiComp.setFrequency(kanjiComp.getFrequency() + 1);
    }
    realm.commitTransaction();
}

Realm.io - 如何更新对象？

Realm.io - How to update object?

android

realm