kobeumut

fun <T> LiveData<T>.observeOnce(lifecycleOwner: LifecycleOwner, observer: Observer<T>) {
    observe(lifecycleOwner, object : Observer<T> {
        override fun onChanged(t: T?) {
            observer.onChanged(t)
            removeObserver(this)
        }
    })
}
//Using
liveData.observeOnce(this, Observer<Password> {

kobeumut

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.util.Base64;

public class Encryptor {
    public static String encrypt(String key, String initVector, String value) {
        try {
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));

kobeumut

extension CheckData on List? {
  T getItem<T>(int position,{dynamic errorReturnValue = "."}) => (this?.length ?? 0) > position ? this![position] : errorReturnValue;
}

//USAGE
// var list = [1,2,5,7];
// print("${list[4]}");  this shows index out of range error so now you can use like below
// list.getItem(4) it's return dot because of the default errorReturnValue is .
//
// if you want specify the error value you can enter errorReturnValue parameter

kobeumut

public class ApplicationExecutors {

    private final Executor background;
    private final Executor mainThread;

    public Executor getBackground() {
        return background;
    }

    public Executor getMainThread() {

kobeumut

//Checkbox
import UIKit

class CheckBox: UIButton {
    // Images
    let checkedImage = UIImage(named: "ic_check_box")! as UIImage
    let uncheckedImage = UIImage(named: "ic_check_box_outline_blank")! as UIImage

    // Bool property
    var isChecked: Bool = false {

kobeumut

fun ViewGroup.findViewWithTagRecursively(tag: Any): List<View>? {
    val allViews: MutableList<View> = ArrayList<View>()
    val childCount: Int = this.childCount
    for (i in 0 until childCount) {
        val childView: View = this.getChildAt(i)
        if (childView is ViewGroup) {
            childView.findViewWithTagRecursively(tag)?.let { allViews.addAll(it) }
        } else {
            val tagView: Any? = childView.tag
            if (tagView != null && tagView == tag) allViews.add(childView)

kobeumut

//Xib class
import UIKit

protocol CustomViewDelegate: class {         // make this class protocol so you can create `weak` reference
    func goToNextScene()
}

class CustomView: UIView {

    weak var delegate: CustomViewDelegate?   // make this `weak` to avoid strong reference cycle b/w view controller and its views

kobeumut

import java.text.SimpleDateFormat
import java.util.*

/**
 * Pattern: yyyy-MM-dd HH:mm:ss
 */
fun Date.formatToServerDateTimeDefaults(): String{
    val sdf= SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault())
    return sdf.format(this)
}

kobeumut

Call<ResponseBody>.saveFile(fileNameWithExt: String, action: (file: File?) -> Unit) {
        GlobalScope.launch {
            try {
                cacheDir.listFiles { _, name -> name.contains("${fileType}.pdf") }?.lastOrNull {
                    action(it)
                    true
                }?:
                withContext(Dispatchers.IO) {
                    val response = this@saveFile.execute()
                    val buffer = response.body()?.byteStream()

kobeumut

    fun alternateMerge(arr1: IntArray, arr2: IntArray,
                       n1: Int, n2: Int, arr3: IntArray) {
        var i = 0
        var j = 0
        var k = 0
        // Traverse both array
        while (i < n1 && j < n2) {
            arr3[k++] = arr1[i++]
            arr3[k++] = arr2[j++]
        }