Singleton class with shared preferences, pass in Context everytime or store it

Question

I'm creating a singleton class that is static as it needs to be accessed from everywhere. This class needs to write to shared preferences often. To create Shared references object, I will need context.

I read that it is bad idea to store a reference to Context in a static class as the context can't garbage collected especially if it was activity.

Therefore, I created methods that wherever it needs to write to share preferences, I pass in context. This is resulting in creating shared preferences object, storing data, then deleting the object.

Is this ok? Why or why not?

Thank you

yes it is ok. i use this approach all the time to avoid biolerplate code — Viral Patel, Jan 14 '16 at 07:24

score 4 · Accepted Answer · answered Jan 14 '16 at 07:16

4

Your can simply

SharedPreferences pref = PreferenceManager.
       getDefaultSharedPreferences(context.getApplicationContext());

So whenever context is finalized you won't care because you use application context

answered Jan 14 '16 at 07:16

So it is safe to store ApplicationContext as a variable in static class? – Snake Jan 14 '16 at 07:21

score 0 · Answer 2 · answered Jan 14 '16 at 07:31

public ClassSingle{

       private static ClassSingle classSingle = null;

        public ClassSingle(Context context) {
          //default values of variable if any
        }

       synchronized public static ClassSingle getInstance(Context context) {
           if (classSingle == null) {
               String configJson = context.getSharedPreferences(ApplicationConstants.PREF_FILE_CONFIG, Context.MODE_PRIVATE)
                .getString(ApplicationConstants.EXTRA_KEY, null);
              try {
                  classSingle = new Gson().fromJson(configJson, ClassSingle.class);
              } catch (JsonSyntaxException e) {
                  e.getStackTrace();
              }

              if (classSingle == null) {
                 classSingle = new ClassSingle(context);
         }
      }
      return classSingle;
     }
}

Use this way to make class singlton and to get instance everywhere.. It will create new instance if it not there, otherwise it will return existing instance.

Singleton class with shared preferences, pass in Context everytime or store it

2 Answers2