Using a class to store static data in Java?

Question

Is it a bad idea creating a separate class and use it as a storage which consists only of static data variables?

I am currently developing an app for android, but the question is general for Java.

In case of android, I am moving across activities and I would like to store some global/static flags/varibles in that separate class and being able to access them from any activity I want.

PS. The data is required only for the session time.

For the lifetime of your app it is a good decision. for longlife storage use the sharedpreferences or sqlite. — nano_nano, Aug 28 '12 at 11:12

score 7 · Accepted Answer · answered Aug 28 '12 at 11:12

Well, that's not a bad idea. You can use such type of a class in Android. But a small correction here. Instead of maintaining a class that holds static Data, you can make that class to extend Application class and use it store the data.

Here is a example,

public class HelloApplication extends Application {
        private int globalVariable=1;

        public int getGlobalVariable() {
                return globalVariable;
        }

        public void setGlobalVariable(int globalVariable) {
                this.globalVariable = globalVariable;
        }
        @Override
        public void onCreate() {
                //reinitialize variable
        }
}

And in your Activity, do this,

(HelloApplication)getApplication()).setGlobalVariable(10);
int valiable=((HelloApplication)getApplication()).getGlobalVariable();

Taken from here..

And speak about SharedPreference, you should consider using them only when the value has to be stored for a long time. if not, you should make use of the Application class and use setters and getters which is the legitimate way to do this.

I think one problem is you have to do a cast everytime you want to access or modify a variable. Using a static class with statics methods/variables saves multiples casts and so process and memory, doesn't it ? — Mickäel A., Aug 28 '12 at 11:15
It is not necessary to cast every time if we store the casted object alone and make use of it through out.. — Andro Selva, Aug 28 '12 at 11:16
It is a good idea, but I believe creating setters and getters each time I add a new variable is troublesome. However, I must have a look on advantages using Application extension. — Arturs Vancans, Aug 28 '12 at 11:24

score 5 · Answer 2 · answered Aug 28 '12 at 11:10

5

You can use SharedPreference to store flags and variables .

Look at this Preference Demo .

answered Aug 28 '12 at 11:10

Chirag

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I need it only for a session time and I want the setting to reset on every new app launch. – Arturs Vancans Aug 28 '12 at 13:44

score 2 · Answer 3 · edited May 23 '17 at 12:10

2

Instead of Creating a Static class to save Global Variables, I would suggest you to use Application class.

see Link:

Android global variable

edited May 23 '17 at 12:10

Community

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answered Aug 28 '12 at 11:11

jeet

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score 1 · Answer 4 · answered Aug 28 '12 at 11:11

1

use SharedPreference to store flags and variables

http://developer.android.com/reference/android/content/SharedPreferences.html

For Global variable:

it would be better to use the Android Application class. It's meant to store global application state

answered Aug 28 '12 at 11:11

Mohammod Hossain

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score 1 · Answer 5 · answered Aug 28 '12 at 11:15

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i suggest that "never" use a global variables ....

when you are accessing to another activity you can throw some values using Intent.putExtras(Name_parameter, "value_parameter")

and to recive the value : Bundle b = getIntent().getExtras(); where b has all parameters

cheers,

answered Aug 28 '12 at 11:15

Alex Muni

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The question is not about passing data from an activity to another, it's about accessing data whatever its nature from anywhere in the code. – Mickäel A. Aug 28 '12 at 11:16
Moreover, I meant generally in Java mentioning Android just as an example. – Arturs Vancans Aug 28 '12 at 11:21

score 0 · Answer 6 · answered Aug 28 '12 at 11:13

Well ! As far as I know It might depend on the size of your project ! If its relatively large its good to use separate class to store static data (not only one class , you might come in need of keeping them two or more classes depending on the type of the static data used)

score 0 · Answer 7 · answered Aug 28 '12 at 11:17

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I would suggest that you should encapsulate your global class with a Singleton class. See more at Singleton Design Pattern

answered Aug 28 '12 at 11:17

nick.katsip

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Using a class to store static data in Java?

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