Sharing a variable between many Activities in Android App

Question

I am letting my user login to Facebook, Twitter and G+ on my app. After they log in, I want to know that they are logged in on every activity in my app. I am looking to find a way to find this out on each activity. I know you can pas variables from activity to activity using Intent like this:

            Intent intent = new Intent(MainActivity.this,
                    SecondActivity.class);
            intent.putExtra("loginMethod", "facebook");
            startActivity(intent);

but this is becoming a hassle to do with 10+ activities. Is there any easier way?

score 0 · Answer 1 · answered Jul 31 '14 at 19:59

0

You can use SharedPreferences.

Here is a good tutorial:

http://examples.javacodegeeks.com/android/core/content/android-sharedpreferences-example/

answered Jul 31 '14 at 19:59

Jonas452

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score 0 · Accepted Answer · answered Jul 31 '14 at 19:59

what I recomendo you is to implement shared preferences... going by this way

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        SharedPreferences.Editor editor = preferences.edit();

editor.putstring("loginMethod","Facebook");
editor.commit;

and whenever you want to check the loginMethod value just call the preference value like this...

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());


String loginMethodValue = preferences.getString("loginMethod", "");

if you need more assistant I'll be more than happy to help you

score 0 · Answer 3 · edited May 23 '17 at 12:11

0

You have many ways for doing so.

Store it in a singleton
Use SharedPreferences
You can extend the Application context

More info here

edited May 23 '17 at 12:11

Community

1
1

answered Jul 31 '14 at 20:01

Lior Ohana

3,467
4
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score 0 · Answer 4 · answered Jul 31 '14 at 20:03

I suggest you to use a Singleton class. The mimimum contents of a singleton are:

A static private field of the class type.
Other private fields you need ("business" fields).
A private constructor.
A public static method that returns the only class instance.
The business methods you need.

I usually call it Store, since it plays the role of a common store for the whole application. For example:

public class Store {
    private static Store me;
    private Facebook fb;
    private Twitter twitter;

    private Store() {
         this.fb=new Facebook();
         this.twitter=new Twitter();
    }

    public static Store get() {
         if (me==null) 
             me=new Store();
         return me;
    }

    public void postInFaceBook(FBPost post) {
        this.fb.post(post);
    }

      ...
}

Sometimes you need a context to be shared among activities. In this case, I suggest to pass the application context to the get method:

public class Store {
    private static Store me;
    private Facebook fb;
    private Twitter twitter;
    private Context ctx;

    private Store(Context ctx) {
         this.ctx=ctx;
         this.fb=new Facebook();
         this.twitter=new Twitter();
    }

    public static Store get(Context ctx) {
         if (me==null) 
             me=new Store(ctx);
         return me;
    }

    public void postInFaceBook(FBPost post) {
        this.fb.post(this.ctx, post);
    }

      ...
}

The use of the Store is simply:

public void m(FBPost p) {
    Store.get().postInFacebook(p);
}

The first time the store is used, the only instance (which will be shared by the whole application) will be created; the second and next times, the get method will return the previous existing instance.

Thanks for the post, is there an advantage to using this over SharedPreferences as the others suggested? Just curious is all — Harry, Jul 31 '14 at 20:09
For my is easier since I keep the complete control and do as I want. I've never found any drawback to the use of "singletons". — Macario Polo Usaola, Jul 31 '14 at 20:15
See also the use of a singleton in: [http://stackoverflow.com/questions/7742776/cant-register-receiver-dynamically/25003574#25003574](http://stackoverflow.com/questions/7742776/cant-register-receiver-dynamically/25003574#25003574) — Macario Polo Usaola, Jul 31 '14 at 20:18

Sharing a variable between many Activities in Android App

4 Answers4