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Android Kotlin Tutorial Day 3

Android Kotlin Tutorial Day 3

Learning Objective: Let’s try some most important codes like saving data into SharedPreference using Kotlin, Call Online API, and Display Static value into ListView.

SharedPreference Example

val sharedpreferences = requireContext().getSharedPreferences(
                MyPREFERENCES,
                Context.MODE_PRIVATE
            )
            val name = "Adarsh"
            val editor = sharedpreferences.edit()
            editor.putString("name", name)
            editor.commit()
            Toast.makeText(context, "Pref Saved", Toast.LENGTH_SHORT).show()

Call API Online 

fun callAPI() {

        // Instantiate the RequestQueue.
        val queue: RequestQueue = Volley.newRequestQueue(context)
        val url = "https://jsonplaceholder.typicode.com/todos/1"


        // Request a string response from the provided URL.
        val stringRequest = StringRequest(
            Request.Method.GET, url,
            Response.Listener<String> { response ->

                    Log.e("cs", response)
                    try {
                        val obj = JSONObject(response)
                        Log.e("cs", obj.getString("userId"))
                        Log.e("cs", obj.getString("id"))
                        Log.e("cs", obj.getString("title"))
                        Log.e("cs", obj.getString("completed"))
                    } catch (t: Throwable) {
                        Log.e("cs", "Could not parse malformed JSON: \"" + "" + "\"")
                    }
            }, object : Response.ErrorListener {
                override fun onErrorResponse(error: VolleyError) {
                    Log.e("cs", error.toString())
                }
            })

        // Add the request to the RequestQueue.
        queue.add(stringRequest)
    }

ListView Display Items

fragment_second.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".SecondFragment">

    <!-- TODO: Update blank fragment layout -->

    <ListView
        android:id="@+id/list1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>


</LinearLayout>

SecondFragment.kt

package com.example.kotlin1

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ArrayAdapter
import android.widget.ListView
import androidx.fragment.app.Fragment
import com.example.kotlin1.databinding.FragmentSecondBinding


/**
 * A simple [Fragment] subclass as the second destination in the navigation.
 */
class SecondFragment : Fragment() {

    private var _binding: FragmentSecondBinding? = null
    var list1: ListView? = null
    var courses = arrayOf("BCA", "PGDCA", "MCA", "MBA")

    // This property is only valid between onCreateView and
    // onDestroyView.
    private val binding get() = _binding!!

    override fun onCreateView(
            inflater: LayoutInflater, container: ViewGroup?,
            savedInstanceState: Bundle?
    ): View? {

        val view: View = inflater.inflate(R.layout.fragment_second, container, false)

        list1 = view.findViewById<View>(R.id.list1) as ListView
        val arr1: ArrayAdapter<String>

        arr1 = ArrayAdapter(
            requireContext(),
            androidx.appcompat.R.layout.support_simple_spinner_dropdown_item,
            courses
        )
        list1!!.adapter = arr1

        // Inflate the layout for this fragment

        // Inflate the layout for this fragment
        return view
       /* _binding = FragmentSecondBinding.inflate(inflater, container, false)
        return binding.root*/

    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

       /* binding.buttonSecond.setOnClickListener {
            findNavController().navigate(R.id.action_SecondFragment_to_FirstFragment)
        }*/
    }

    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }
}

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