Manage Global Object Or List

I have read many blogs about how singleton are vulnerable in android.so my question is how to maintain such global objects or list in application.i know shared preference is one wa

Solution 1:

You can use a file or SQLite database to save data in android app. You can check below links to learn more about saving data in a file or SQLite database:

Saving data to a file is ideal to store long sequences of data that are generally read in orderhttps://developer.android.com/training/basics/data-storage/files.html

Saving data to a database is ideal for repeating or structured data:https://developer.android.com/training/basics/data-storage/databases.html

Solution 2:

use sharedPreferences, Sqlite database to manage your objects, singletons are not very good, but static variables are more hard to maintain and will make testing the cide more tough, you can use Shared preferences to maintain a global state if the data is not very large, if there is large amount of data then use of sqlite is recommended.

Shared preferences are extremely easy to use, if you have problem using sqlite though you can use orm libraries for android here's a link to one: http://greenrobot.org/greendao/

Solution 3:

If you just want to keep a list as Global until your app is running, then create a new class let's say "Helper" and Initialize a Static List in that class. Now you can access that list anywhere within the app by "Helper.yourStaticListName" and you can also add/remove or get data from the list anywhere within the app. But if you want to keep that list even when app has been closed, then there are two solutions for that. First Create a local database "SQLite file" in your app and add/remove or get data from it.

Check this tutorial: http://www.androidhive.info/2011/11/android-sqlite-database-tutorial/

Second solution is to convert your data into a JSON and convert that JSON into String and save it in Shared Preferences. And whenever you need it just get the string from Shared Preferences and convert it into JSON and parse to get the data. One last thing when you are talking about parsing a JSON, then "GSON library" is a good thing to work with.

Here is the link: http://guides.codepath.com/android/leveraging-the-gson-library

Hope this answer will help you.

Solution 4:

How about using Android Service?

You can initialize / start it when your application started (and also stop them when your application stopped) and then bind them whenever you need (put and get your object / list).

I believe it will be an efficient way.

Solution 5:

From conceptual point having a static variables or service-locators is very similar to having Singletons. Hence, having them as alternatives may not be be correct, if the intention is to avoid the Global state and consequences.

We can change Singleton-classes into instances, which are instantiated only once and injected into the components and methods as needed. We can use a IoC-framework to handle the injection part or do it manually with a factory pattern to construct (we can restrict only one instance creation as well) instances of the classes. This discussion thread gives lot of insights on the problem and various options.