CODEWITHSUNDEEP
javaandroid
tread
tread

Reputation: 11098

How do you persist an object throughout an android application?

When the application loads I do a request to a webservice that returns JSON which is converted to Plain Old Java Objects:

Airports:

public class Airports {

    private List<Airport> airportList = new ArrayList<Airport>();

    ...get and set...
}

Airport:

public class Airport {
    private String id;
    private String airport;
    private String city;

    ...get and set...
}

Now because doing a request everytime is costly, I would like this list of Airports (the airports object) to be accessible throughout the application. How can I access the data of a single instance of this object.

Storing in SQLite would be overkill.

Now I have read about using the Application Subclass, Singleton classes and Shared Preferences.

I am not too sure which solution best fits the problem?

Upvotes: 0

Views: 143

Answers (2)

frogatto
frogatto

Reputation: 29285

Choosing one of the ways you have said is based on what behavior you would want about those data. If you would want stability of those data during application life cycle, using singleton or application subclass would be okay, but otherwise if you want those data to be persistent for ever until the app is installed, you probably need SQLite or file or Shared Preferences. So

Persistent during app life-cycle

  • Java singleton pattern (generally using static members)
  • Sub-classing of Application class

Persistent until app is installed

  • SQLite (usually used for large amount of data)
  • Shared preferences (usually for small data)
  • File

Note that SQLite and shared preferences approach is more structured than using raw files.

Upvotes: 1

SteD
SteD

Reputation: 14027

Store the json in shared preferences if it's not too big (few hundreds sizes in kb).

SharedPreferences.Editor editor = preferences.edit();
editor.putString("jsondata", jsonData.toString());
editor.commit();

Retrieval:

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
String stringJson = sharedPref.getString("jsondata");
if(stringJson != null){
  JSONObject jsonData = new JSONObject(stringJson);
}else{
  //retrieve from web services
}

Upvotes: 1

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