How to save data in an android app

Question

I recently coded an Android app. It's just a simple app that allows you to keep score of a basketball game with a few simple counter intervals. I'm getting demand to add a save feature, so you can save your scores and then load them back up. Currently, when you stop the app, your data is lost. So what I was wondering is what I would have to add to have the app save a label (score) and then load it back up. Thanks guys sorry I don't know much about this stuff.

Answer 1

You have two options, and I'll leave selection up to you.

1. Shared Preferences

   This is a framework unique to Android that allows you to store primitive values (such as int, boolean, and String, although strictly speaking String isn't a primitive) in a key-value framework. This means that you give a value a name, say, "homeScore" and store the value to this key.

   SharedPreferences settings = getApplicationContext().getSharedPreferences(PREFS_NAME, 0);
   SharedPreferences.Editor editor = settings.edit();
   editor.putInt("homeScore", YOUR_HOME_SCORE);
   
   // Apply the edits!
   editor.apply();
   
   // Get from the SharedPreferences
   SharedPreferences settings = getApplicationContext().getSharedPreferences(PREFS_NAME, 0);
   int homeScore = settings.getInt("homeScore", 0);
   

2. Internal Storage

   This, in my opinion, is what you might be looking for. You can store anything you want to a file, so this gives you more flexibility. However, the process can be trickier because everything will be stored as bytes, and that means you have to be careful to keep your read and write processes working together.

   int homeScore;
   byte[] homeScoreBytes;
   
   homeScoreBytes[0] = (byte) homeScore;
   homeScoreBytes[1] = (byte) (homeScore >> 8);  //you can probably skip these two 
   homeScoreBytes[2] = (byte) (homeScore >> 16); //lines, because I've never seen a                   
                                                 //basketball score above 128, it's
                                                 //such a rare occurance.
   
   FileOutputStream outputStream = getApplicationContext().openFileOutput(FILENAME, Context.MODE_PRIVATE);
   outputStream.write(homeScoreBytes);
   outputStream.close();
   

Now, you can also look into External Storage, but I don't recommend that in this particular case, because the external storage might not be there later. (Note that if you pick this, it requires a permission)