[英]Realm: update id of foreign obect
我從API獲取以JSON作為業務清單。 此列表可以更改,因此我需要定期調用它以更新數據。 每個公司都有一個地址,但該地址沒有id 。 因為這是服務器中的OneToOne關系,所以不需要主鍵。 但是在客戶端,Realm需要和主鍵才能使用copyToRealmOrUpdate() 。 所以我在地址類中添加了一個ID以便能夠使用它
這是我的代碼
商務課程
public class Business extends RealmObject{
@PrimaryKey
private int id;
private Category category;
private String name;
private String description;
private String telephone;
private String fax;
private String email;
private String website;
private Address address;
//getters and setters
}
地址類別
public class Address extends RealmObject{
@PrimaryKey
private int id ;
@SerializedName("street_type")
private String streetType;
@SerializedName("street_number")
private String streetNumber;
@SerializedName("street_name")
private String streetName;
private String direction;
private String city;
private String province;
@SerializedName("postal_code")
private String postalCode;
public Address (){ }
public void setAddress(Address a){
this.streetName = a.getStreetName();
this.streetType = a.getStreetType();
this.direction = a.getDirection();
this.city = a.getCity();
this.province = a.getProvince();
this.streetNumber = a.getStreetNumber();
this.postalCode = a.getPostalCode();
}
//other getters and setters
}
JSON范例
[
{
"id": 2,
"address": {
"business": 2,
"street_number": 1111,
"street_type": "ST",
"street_name": " STREET NAME",
"direction": "",
"city": "CITY",
"province": "QC",
"postal_code": "H0H 0H0"
},
"category": {
"id": 1,
"name": "Restaurant",
"active": true
},
"name": "Business",
"description": "a description",
"email": "",
"person_in_charge": "",
"website": "",
"telephone": "(514) 555-5555",
"fax": "",
},
//others business
]
從API檢索業務
Realm realm = Realm.getDefaultInstance();
List<Business> businesses = null;
try {
businesses = new CallGenerator<List<Business>, BusinessService>().asynAPICall(
new CallGenerator.AsynAPICallback<BusinessService>() {
@Override
public Call onApiCall(BusinessService client) {
return client.getBusinessesByCategory(null);
}
}, BusinessService.class).execute().get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
for (Business b : businesses) {
Address realmAddress = realm.where(Address.class).equalTo("id", b.getId()).findFirst();
realm.beginTransaction();
if (realmAddress == null)
realmAddress = realm.createObject(Address.class, b.getId());
realmAddress.setAddress(b.getAddress());
b.setAddress(realmAddress);
realm.copyToRealmOrUpdate(b);
realm.commitTransaction();
}
問題是每個業務中的地址都不會保存,因此在我打電話給他們時總是為空。 我可以通過以下查詢獲得地址:
Address a = realm.where(Address.class).equalTo("id",business.id).findFirst();
但不是這樣的:
Business mBusiness = realm.where(Business.class).equalTo("id", id).findFirst();
mBusiness.getAddress//always null
Address realmAddress = realm.createObject(Address.class,b.getId());
應該
Address realmAddress = realm.where(Address.class).equalTo("id", b.getId()).findFirst();
if(realmAddress == null) {
realm.createObject(Address.class,b.getId());
}
但是,如果您想對此進行優化,可能是
realm.executeTransaction(new Realm.Transaction() {
@Override
public void execute(Realm realm) {
Address realmAddress = new Address();
for (Business b : businesses) {
realmAddress.setId(b.getId())
realmAddress.setStreetName(b.getAddress().getStreetName());
realmAddress.setStreetType(b.getAddress().getStreetType());
realmAddress.setDirection(b.getAddress().getDirection());
realmAddress.setCity(b.getAddress().getCity());
realmAddress.setProvince(b.getAddress().getProvince());
realmAddress.setStreetNumber(b.getAddress().getStreetNumber());
realm.insertOrUpdate(realmAddress);
Log.i(TAG,"New address id "+realmAddress.getId() +" with address "+ realmAddress);
}
List<Business> realmRepos = realm.copyToRealmOrUpdate(businesses);
}
});
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