How to Read AsyncStorage on Android Correctly

Question

It seems that it\'s possible access the AsyncStorage from Android (native); but I still struggling to make this work.

In my React Native application, I

Answer 1

I had a problem with alarm clock in my application and I decided to use AsyncStorage on Android side, then I use the code below and I could get all values from AsyncStorage and generate all alarms that was registered in my application's AsyncStorage.

SQLiteDatabase readableDatabase = null;
        readableDatabase = ReactDatabaseSupplier.getInstance(this.reactContext).getReadableDatabase();
        Cursor catalystLocalStorage = readableDatabase.query("catalystLocalStorage", null, null, null, null, null, null);
        try {
            List<AlarmeDTO> listaAlarmes = new ArrayList<>();
            if (catalystLocalStorage.moveToFirst()) {

                do {
                    //Ex: key: 01082019_0800
                    //value: [{executionDate: 2019-08-01T08:00}]
                    String key = catalystLocalStorage.getString(0);
                    String json = catalystLocalStorage.getString(1);

                    if (dados.length == 3) {
                        ...generate my alarms with key and json
                    }

                } while (catalystLocalStorage.moveToNext());

            }//2_31082019_0900 - [{"idPrescricaoMedicamento":35,"nomeMedicamento":"VITAMINA"}]

        } finally {
            if (catalystLocalStorage != null) {
                catalystLocalStorage.close();
            }

            if (readableDatabase != null) {
                readableDatabase.close();
            }
        }

Answer 2

AsyncStorage it's an unique JSON Object and instead I was expecting many rows of key and value; That's why I was getting null.

So first I continue with the query

catalystLocalStorage = readableDatabase.query("catalystLocalStorage", new String[]{"key", "value"}, null, null, null, null, null);

then I check to avoid null pointer

if (catalystLocalStorage.moveToFirst()) {

then I do the fetch

do {
    // JSONObject will ask for try catch
    JSONObject obj = new JSONObject(catalystLocalStorage.getString(catalystLocalStorage.getColumnIndex("value")));
} while(catalystLocalStorage.moveToNext());

I'm sure that may have better ways to do this, but right know I'm fine with that.

If you have better ideas please leave your thought.

UPDATE

import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.bridge.ReactContextBaseJavaModule;
import com.facebook.react.modules.storage.ReactDatabaseSupplier;
import org.json.JSONArray;
import org.json.JSONObject;
import java.util.ArrayList;

public class AsyncStorage {

    public static String TAG = "RNAsyncStorage";
    public ReactApplicationContext context;
    public ArrayList<JSONObject> collection;
    public JSONObject data;
    public JSONObject user;

    Cursor catalystLocalStorage = null;
    SQLiteDatabase readableDatabase = null;

    public AsyncStorage (ReactApplicationContext context) {
        this.context = context;
        this.collection = new ArrayList<JSONObject>();
        this.fetch();
        this.setUser();
    }

    public void fetch() {
        try {
            readableDatabase = ReactDatabaseSupplier.getInstance(context).getReadableDatabase();
            catalystLocalStorage = readableDatabase.query("catalystLocalStorage", new String[]{"key", "value"}, null, null, null, null, null);

            if (catalystLocalStorage.moveToFirst()) {
                do {
                    try {
                        // one row with all AsyncStorage: { "user": { ... }, ... }
                        String json = catalystLocalStorage.getString(catalystLocalStorage.getColumnIndex("value"));
                        JSONObject obj = new JSONObject(json);

                        String user = obj.getString("user");

                        JSONObject res = new JSONObject();
                        res.put("user", new JSONObject(user));

                        collection.add(res);
                    } catch(Exception e) {
                        // do something
                    }
                } while(catalystLocalStorage.moveToNext());
            }
        } finally {
            if (catalystLocalStorage != null) {
                catalystLocalStorage.close();
            }

            if (readableDatabase != null) {
                readableDatabase.close();
            }

            data = this.collection.get(0);
        }
    }

    public String getFullname () {
        try {
            return user.getString("fullname");
        } catch (Exception e) {
            return "";
        }
    }
}

Calling the class

AsyncStorage as = new AsyncStorage(context);
as.getFullname()