Android - Shared Preferences

Android provides many ways of storing data of an application. One of this way is called Shared Preferences. Shared Preferences allow you to save and retrieve data in the form of key,value pair.

In order to use shared preferences, you have to call a method getSharedPreferences() that returns a SharedPreference instance pointing to the file that contains the values of preferences.

SharedPreferences sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);

The first parameter is the key and the second parameter is the MODE. Apart from private there are other modes available that are listed below −

Sr.No	Mode & description
1	MODE_APPEND This will append the new preferences with the already existing preferences
2	MODE_ENABLE_WRITE_AHEAD_LOGGING Database open flag. When it is set , it would enable write ahead logging by default
3	MODE_MULTI_PROCESS This method will check for modification of preferences even if the sharedpreference instance has already been loaded
4	MODE_PRIVATE By setting this mode, the file can only be accessed using calling application
5	MODE_WORLD_READABLE This mode allow other application to read the preferences
6	MODE_WORLD_WRITEABLE This mode allow other application to write the preferences

You can save something in the sharedpreferences by using SharedPreferences.Editor class. You will call the edit method of SharedPreference instance and will receive it in an editor object. Its syntax is −

Editor editor = sharedpreferences.edit();

editor.putString("key", "value");

editor.commit();

Get a handle to shared preferences

Context context = getActivity();
SharedPreferences sharedPref = context.getSharedPreferences(
        getString(R.string.preference_file_key), Context.MODE_PRIVATE);

or 

SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);

Write to shared preferences

SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putInt(getString(R.string.saved_high_score_key), newHighScore);
editor.apply();

Read from shared preferences

SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
int defaultValue = getResources().getInteger(R.integer.saved_high_score_default_key);
int highScore = sharedPref.getInt(getString(R.string.saved_high_score_key), defaultValue);