java - Realm RecyclerAdapter 返回单个项目

Question

我正在从 json api 获取数据，我已将 PrimaryKey 设置为状态。这是我正在获取的 Json 数据:

records[
  {  
         "id":"192693681",
         "timestamp":"1500204608",
         "state":"Rajasthan",
         "district":"Rajasamand",
         "market":"Rajasamand",
         "commodity":"Sugar",
         "variety":"Shakkar",
         "arrival_date":"16/07/2017",
         "min_price":"4000",
         "max_price":"4100",
         "modal_price":"4050"
      },
      {  
         "id":"192693701",
         "timestamp":"1500204608",
         "state":"Rajasthan",
         "district":"Rajasamand",
         "market":"Rajasamand",
         "commodity":"Wheat",
         "variety":"Farmi",
         "arrival_date":"16/07/2017",
         "min_price":"1600",
         "max_price":"1650",
         "modal_price":"1625"
      },
      {  
         "id":"192693721",
         "timestamp":"1500204608",
         "state":"Rajasthan",
         "district":"Rajasamand",
         "market":"Rajasamand",
         "commodity":"Wheat",
         "variety":"Lokwan",
         "arrival_date":"16/07/2017",
         "min_price":"1550",
         "max_price":"1600",
         "modal_price":"1575"
      }
   ]

这是我返回每个州的市场数据的查询:

private void populateMarketData(String state){
        cityAdapter = new CityAdapter(mRealm.where(Records.class).equalTo(Constants.STATE, state).findAll(), this);
        cityRecyclerView.setAdapter(cityAdapter);
        Log.d(TAG, "Total Cities" + String.valueOf(cityAdapter.getData().size()));
        cityAdapter.notifyDataSetChanged();
    } 

这是我的查询，用于返回具有以下状态的市场的所有商品:

 @Override
    public void onMarketClicked(String cityName) {
        tradeAdapter = new TradeAdapter(mRealm.where(Records.class)
                .equalTo(Constants.MARKET, cityName).findAll(), this);
        tradeRecyclerView.setAdapter(tradeAdapter);
    }

这是GcmTaskService，用于更新后台服务中的数据:

Realm.init(mContext);
        List<Records> records = new MandiDataHandler().getMandiQuotes(url);
        SaveMandi saveMandi = new SaveMandi(state, records);
        Realm realm = new RealmController(getApplication()).getRealm();
        realm.beginTransaction();
        realm.copyToRealmOrUpdate(saveMandi);
        realm.commitTransaction();
        realm.close();

这是DataHelper，用于保存来自Json API的数据

@PrimaryKey
    private String state;

    private RealmList<Records> recordsRealmList = new RealmList<>();

    public SaveMandi(){}

    public SaveMandi(String state, List<Records> recordsList) {

        try {
            this.state = state;
            for (Records records: recordsList ) {
                records = new Records(records.getId(), DateUtils.getRelativeTimeSpanString(
                        Long.parseLong(records.getTimestamp())).toString(), records.getState(), records.getMarket(),
                        records.getCommodity(), records.getVariety(), records.getMin_price(), records.getMax_price());
                this.recordsRealmList.add(records);
            }

        }catch (Exception e){
            e.printStackTrace();
        }
    }

我的RealmRecyclerView中的问题是，当我将PrimaryKey设置为state时，它返回单个项目，否则当我将PrimaryKey设置为id时，它返回单个项目它返回多个重复数据。我不确定我哪里可能错了。

Answer 1

您想选择您的PrimaryKey只有当它们(你认为)“相等”时才会匹配，就像 equals()方法。如果你放两个 RealmObjects与相同的PrimaryKey进入 Realm 后，只有其中一个会出现在 Realm 中，因为每个不同的对象只能有一个 PrimaryKey .

例如，如果我有 RealmObject a与 PrimaryKey的1在 Realm 中，我又放了另一个 RealmObject b与 PrimaryKey的1进入 Realm ，a将被删除 b因为每个 PrimaryKey 只能有一个对象.

查看 Realm 数据库的一个好工具是 Stetho ，我强烈推荐使用 Realm 来调试应用程序。