在所有活动中存储和访问变量的最佳方法是什么？

Question

I have an app in which I have more than 450 custom Java objects, and about 200 other variables of strings, int, etc. I know that these much variables use large RAM of the device, so I want to know the best way for storing and accessing them. Some variables are used in many activities.

Answer 1

you can use data base for storing variables in memory but it better to use Sharedprefrences to store all variables :

SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", 0); 
Editor editor = pref.edit();
editor.putBoolean("key_name", true); 
editor.commit();

and easilly get the variable :

pref.getString("key_name", null);

Answer 2

I would definitely persist them to aa file since they are so many. Doing this you can load the classes in when you need them and not worry about memory

Saving custom class

FileOutputStream fos = context.openFileOutput(fileName, Context.MODE_PRIVATE);
ObjectOutputStream os = new ObjectOutputStream(fos);
os.writeObject(this);
os.close();
fos.close();

Loading custom Class

FileInputStream fis = context.openFileInput(fileName);
ObjectInputStream is = new ObjectInputStream(fis);
SimpleClass simpleClass = (SimpleClass) is.readObject();
is.close();
fis.close();

Here´s another question with some cool implementations of this