How to send data another page and list with kotlin? - kotlin

Question

I just started learning Kotlin. I am making an application that saves bank (IBAN) information. I save the information locally using sharedpreferences.
I save the information to the list and save it as sharedpreferences.
Information is recorded on page 2 and I want to list this recorded information on page 1.
I was doing this simply in Flutter, but I couldn't understand how to do it in Kotlin.
package com.example.ibansfer
import android.os.Bundle
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.example.ibansfer.databinding.ActivityAddIbanBinding
import com.example.ibansfer.models.IbanModel
import com.google.gson.Gson
import com.google.gson.reflect.TypeToken
class AddIbanActivity : AppCompatActivity() {
private lateinit var binding: ActivityAddIbanBinding
private var ibanList: ArrayList<IbanModel> = ArrayList()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityAddIbanBinding.inflate(layoutInflater)
setContentView(binding.root)
setTitle("IBAN bilgisi ekle")
getSupportActionBar()?.setDisplayHomeAsUpEnabled(true);
val sharedPreferences = this.getSharedPreferences("ibans", MODE_PRIVATE)
val editor = sharedPreferences.edit()
fun saveData() {
val gson = Gson()
val json = gson.toJson(ibanList)
editor.putString("ibans", json)
editor.apply()
}
binding.ibanSaveBttn.setOnClickListener {
val ibanOwner = binding.ibanOwner.text.toString()
val bankName = binding.bankName.text.toString()
val ibanAdress = binding.ibanAdress.text.toString()
if (ibanOwner.isEmpty() || bankName.isEmpty() || ibanAdress.isEmpty()) {
Toast.makeText(this, "Lütfen tüm alanları doldurunuz.", Toast.LENGTH_LONG).show()
} else {
ibanList.add(IbanModel(ibanOwner, bankName, ibanAdress))
saveData()
Toast.makeText(this, "IBAN bilgileri başarıyla eklendi.", Toast.LENGTH_LONG).show()
finish()
}
}
}
}

Answer 1

If you save the data in SharedPrefferences, you can always retrieve it back in the other screen.
val sharedPref = activity?.getPreferences("ibans", Context.MODE_PRIVATE) ?: return
val myString = sharedPref.getString("ibans", defaultValue)
You can even set up a SharedPrefferences listener that will get notified whenever new data is added to it and act accordingly.
val sharedPreferencesListener =
SharedPreferences.OnSharedPreferenceChangeListener { sharedPreferences, key ->
// code to execute on changes here
}
activity?.getPreferences("ibans", Context.MODE_PRIVATE)
?.registerOnSharedPreferenceChangeListener(sharedPreferencesListener )
Also don't forget to unregister using unregisterOnSharedPreferenceChangeListener
Or alternatively, use Intents as the comment suggests to pass data between Activities/Fragments.