Preferences.java

// Source: https://stackoverflow.com/questions/17753800/android-default-values-for-shared-preferences

public class Preferences {
    public static final String MY_PREF = "MyPreferences";

    private SharedPreferences sharedPreferences;
    private Editor editor;

    public Preferences(Context context) {
        this.sharedPreferences = context.getSharedPreferences(MY_PREF, 0);
        this.editor = this.sharedPreferences.edit();
    }

    public void set(String key, String value) {
        this.editor.putString(key, value);
        this.editor.commit();
    }

    public String get(String key) {
        return this.sharedPreferences.getString(key, null);
    }

    public void clear(String key) {
        this.editor.remove(key);
        this.editor.commit();
    }

    public void clear() {
        this.editor.clear();
        this.editor.commit();
    }
}