我正在使用0.81.1版本的Realm。我有这门课:
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;
}
}
我第一次创建这样的对象:
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,我需要一种方法来帮助我更新频率。
Realm文档说明了这一点:
使用主键可以使用createOrUpdate() 方法,它将查找具有此主键的现有对象, 如果找到一个就更新它;如果没有找到,它将创建一个新的 而不是对象。
但我找不到createOrUpdate()方法。使用JSON的所有方法。
我的完整代码如下:
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,如何更新我的对象的值?有没有办法增加我的对象的价值?
答案 0 :(得分:18)
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();
}