How to save variable data in Kotlin-CodePudding

I'm trying to make this so that is saves every time I close the app. The tutorials I found are not clear for me, can anyone please assist me? If needed, here's how my variable I want saved is defined:

private var coins = 0

Here is the GitHub link if needed, which goes straight to MainActivity.

CodePudding user response：

You can use shared preferences to save and retrieve simple data

save data

val sharedPref = activity?.getPreferences(Context.MODE_PRIVATE) ?: return
with (sharedPref.edit()) {
    putInt("MY_COINS", coins)
    apply()
}

Read data

val sharedPref = activity?.getPreferences(Context.MODE_PRIVATE) ?: return
val coins = sharedPref.getInt("MY_COINS"), defaultValue)

CodePudding user response：

You can use Shared Preferences for state management or save data in key-value pair.

lateinit var shared : SharedPreferences

 override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_spactivity)

        shared = getSharedPreferences("CoinsDB" , Context.MODE_PRIVATE)
        var coins = 0

For Save

 val edit = shared.edit()
 edit.putInt("coins" , coins )
 edit.apply()

For retrieve or read

val coinsValue = shared.getInt("coins")

CodePudding user response：

I recommend using storage in files if that isn't a problem for you.