CODEWITHSUNDEEP
javaandroidandroid-preferences
Ethan Allen
Ethan Allen

Reputation: 14845

Is there a way to make SharedPreferences global throughout my whole Android app?

Is there a way to make SharedPreferences global throughout my whole app? Right now I'm using these lines in a lot of places throughout my code to store simple on/off settings for a number of preferences that my users can set. I just want to call them once globally if possible:

SharedPreferences settings = getSharedPreferences("prefs", 0);
SharedPreferences.Editor editor = settings.edit();

Any tips on how to be able to call just these line in all classes would be awesome:

editor.putString("examplesetting", "off");
editor.commit();

and

String checkedSetting = settings.getString("examplesetting", "");

Upvotes: 14

Views: 19370

Answers (4)

t0mm13b
t0mm13b

Reputation: 34598

Use a singleton class that wraps around the SharedPreference settings.. something like this:

public class PrefSingleton{
   private static PrefSingleton mInstance;
   private Context mContext;
   //
   private SharedPreferences mMyPreferences;

   private PrefSingleton(){ }

   public static PrefSingleton getInstance(){
       if (mInstance == null) mInstance = new PrefSingleton();
       return mInstance;
   }

   public void Initialize(Context ctxt){
       mContext = ctxt;
       //
       mMyPreferences = PreferenceManager.getDefaultSharedPreferences(mContext);
   }
}

And create wrapper functions around what your examples represented in the question, for example,

PrefSingleton.getInstance().writePreference("exampleSetting", "off");

and the implementation could be something like this:

// Within Singleton class

public void writePreference(String key, String value){
     Editor e = mMyPreference.edit();
     e.putString(key, value);
     e.commit();
}

From your first activity, activate the singleton class, in this manner, something like this:

PrefSingleton.getInstance().Initialize(getApplicationContext());

Using global static classes can be a bad idea and goes against the practice of programming fundamentals. BUT having said that, as nit-picky aside, it will ensure only the one and only object of the class PrefSingleton can exist and be accessible regardless of what activities the code is at.

Upvotes: 19

user1869209
user1869209

Reputation:

I would do this following :

public class BaseActivity extends Activity {

        protected boolean setInHistory;
        protected SharedPreferences sharedPrefs;

            @Override
        protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this);
    setInHistory = true;
       }


}


public class MainActivity extends BaseActivity {

         public void onCreate(Bundle savedInstanceState) {
               super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);

              System.out.println(setInHistory+" <-- setInhistory");

          }
}

Then can access sharedPrefs because it is protected then it's accessible through the package.

In the console you have : true <-- setInhistory

Upvotes: 3

gobernador
gobernador

Reputation: 5739

I would extend Application and include the SharedPreferences.Editor as a field with a getter.

public class APP extends Application {
    private final SharedPreferences settings = getSharedPreferences("prefs", 0);
    private final SharedPreferences.Editor editor = settings.edit();

    public SharedPreferences.Editor editSharePrefs() {
        return editor;
    }
}

Then you can access it from any Activity with

((APP) getApplication()).editSharePrefs().putString("examplesetting", "off");
((APP) getApplication()).editsharePrefs().commit();

Alternatively, you could also throw in the method

    public static APP getAPP(Context context) {
        return (APP) context.getApplicationContext();
    }

Although, this would simply change the calls you make to 

APP.getAPP(this).editSharePrefs().putString("examplesetting", "off");
APP.getAPP(this).editsharePrefs().commit();

So it really is a personal preference, which looks cleaner to you.

Upvotes: 11

Clover
Clover

Reputation: 46

Use a Helper class to get all you want,make the methods static.This is how ADW do.

Upvotes: 0

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