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Interview Questions

Kotlin

Q1: What is a primary constructor in Kotlin? ☆☆

Answer: The primary constructor is part of the class header. Unlike Java, you don't need to declare a constructor in the body of the class. Here's an example:

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#Intro

Kotlin is a new programming language for the JVM. It produces Java bytecode, supports Android and generates JavaScript. The latest version of the language is Kotlin M5.3

Kotlin project website is at kotlin.jetbrains.org.

All the codes here can be copied and run on Kotlin online editor.

Let's get started.

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enum class NetworkStatus {
    INITIAL,SUCCESS, ERROR, UNAUTHORIZED
}

suspend fun <T> safeApiCall(dispatcher: CoroutineDispatcher, apiCall: suspend () -> T): Resource<T> {
    return withContext(dispatcher) {
        try {
            Resource.success(apiCall.invoke())
        } catch (exception:Exception) {
            Timber.e("error $exception")

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<paths>
    <external-path
        name="external"
        path="." />
    <external-files-path
        name="external_files"
        path="." />
    <cache-path
        name="cache"
        path="." />

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import android.content.Context;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Build;
import android.provider.MediaStore;

import java.io.File;
import java.io.FileInputStream;

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private void showDialog(){
AlertDialog.Builder builder = new androidx.appcompat.app.AlertDialog.Builder(this);
            builder.setTitle(R.string.exit);
            builder.setMessage(R.string.exit_text);
            builder.setPositiveButton(getResources().getString(R.string.yes), (dialog, arg1) -> finishAffinity());
            builder  .setNegativeButton(getResources().getString(R.string.no), (dialog, arg1) -> dialog.dismiss());
            androidx.appcompat.app.AlertDialog dialog = builder.create();
            dialog.getWindow().getAttributes().windowAnimations = R.style.DialogAnimation_2;
            dialog.show();
            }

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public class CustomAutoCompleteAdapter extends ArrayAdapter<CustomModel> implements Filterable {

    private List<CustomModel> fullList;
    private List<CustomModel> mOriginalValues;
    private ArrayFilter mFilter;

    public CustomAutoCompleteAdapter(Context context, int resource, List<CustomModel> objects) {
        super(context, resource, objects);
        fullList = objects;
        mOriginalValues = new ArrayList<>(fullList);

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String[] PERMISSIONS = {Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE};
    private int RC_PERMISSIONS = 1;
    private long downloadID;
    private BroadcastReceiver onDownloadComplete = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            //Fetching the download id received with the broadcast
            long id = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
            //Checking if the received broadcast is for our enqueued download by matching download id
            if (downloadID == id) {