Here I collect some of my most useful Kotlin extensions

Extensions.kt

inline fun SharedPreferences.edit(changes: SharedPreferences.Editor.() -> SharedPreferences.Editor) {
    edit().changes().apply()
}

fun ImageView.tintSrc(@ColorRes colorRes: Int) {
    val drawable = DrawableCompat.wrap(drawable)
    DrawableCompat.setTint(drawable, ContextCompat.getColor(context, colorRes))
    setImageDrawable(drawable)
    if (drawable is TintAwareDrawable) invalidate() // Because in this case setImageDrawable will not call invalidate()
}

fun ViewGroup.inflate(@LayoutRes layoutRes: Int, attachToRoot: Boolean = false): View {
    return LayoutInflater.from(context).inflate(layoutRes, this, attachToRoot)
}

/**
 * Compat version of setExactAndAllowWhileIdle()
 */
fun AlarmManager.setExactAndAllowWhileIdleCompat(alarmType: Int, timeMillis: Long, pendingIntent: PendingIntent) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        // This version added Doze
        setExactAndAllowWhileIdle(alarmType, timeMillis, pendingIntent)

    } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
        // This version changed set() to be inexact
        setExact(alarmType, timeMillis, pendingIntent)

    } else {
        set(alarmType, timeMillis, pendingIntent)
    }
}

/**
 * Helps to set clickable part in text.
 *
 * Don't forget to set android:textColorLink="@color/link" (click selector) and
 * android:textColorHighlight="@color/window_background" (background color while clicks)
 * in the TextView where you will use this.
 */
fun SpannableString.withClickableSpan(clickablePart: String, onClickListener: () -> Unit): SpannableString {
    val clickableSpan = object : ClickableSpan() {
        override fun onClick(widget: View?) = onClickListener.invoke()
    }
    val clickablePartStart = indexOf(clickablePart)
    setSpan(clickableSpan,
            clickablePartStart,
            clickablePartStart + clickablePart.length,
            Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
    return this
}

/**
 * Helps to get Map, List, Set or other generic type from Json using Gson.
 */
inline fun <reified T: Any> Gson.fromJsonToGeneric(json: String): T {
    val type = object : TypeToken<T>() {}.type
    return fromJson(json, type)
}

// The way to pass server errors from custom error response to the Rx onError. 
// BaseReply has field error: ApiError and ApiError extends Exception.
fun <T : BaseReply> Single<T>.apiErrorsToOnError(): Single<T> {
    // .map the source and
    return this.map { reply ->
        // throw if reply with error or
        reply.error?.let { throw it }
        // return if not
        reply
    }
}

// Adds polling to the request. BaseReply is general response type that has error field
fun <T : BaseReply> Single<T>.poll(delay: Long, errorConsumer: Consumer<Throwable>): Observable<T> = this
        .repeatWhen { completed -> completed.delay(delay, TimeUnit.SECONDS) }
        .doOnError { errorConsumer.accept(it) }
        .retryWhen { errors -> errors.delay(delay, TimeUnit.SECONDS) }
        .toObservable()

fun View.visible(visible: Boolean, useGone: Boolean = true) {
    this.visibility = if (visible) View.VISIBLE else if (useGone) View.GONE else View.INVISIBLE
}

// Helps to set status bar color with api version check
fun Activity.setStatusBarColor(@ColorRes colorRes: Int): Unit {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        window.statusBarColor = ContextCompat.getColor(this, colorRes)
    }
}

// Adds flags to make window fullscreen
fun Activity.setFullscreenLayoutFlags() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        window.decorView.systemUiVisibility = View.SYSTEM_UI_FLAG_LAYOUT_STABLE or
                View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
    }
}

// Adds window insets to the view while entire activity is fullscreen. 
fun View.applyWindowInsets(applyTopInset: Boolean = true, applyOtherInsets: Boolean = true): Unit {
    if (applyTopInset || applyOtherInsets) {
        ViewCompat.setOnApplyWindowInsetsListener(
                this,
                { view, insets ->
                    // Set padding for needed insets
                    view.setPadding(
                            if (applyOtherInsets) insets.systemWindowInsetLeft else view.paddingLeft,
                            if (applyTopInset) insets.systemWindowInsetTop else view.paddingTop,
                            if (applyOtherInsets) insets.systemWindowInsetRight else view.paddingRight,
                            if (applyOtherInsets) insets.systemWindowInsetBottom else view.paddingBottom
                    )

                    // Return without consumed insets
                    insets.replaceSystemWindowInsets(
                            if (applyOtherInsets) 0 else insets.systemWindowInsetLeft,
                            if (applyTopInset) 0 else insets.systemWindowInsetTop,
                            if (applyOtherInsets) 0 else insets.systemWindowInsetRight,
                            if (applyOtherInsets) 0 else insets.systemWindowInsetBottom
                    )
                })
    } else {
        // Listener is not needed
        ViewCompat.setOnApplyWindowInsetsListener(this, null)
    }
}

fun Activity.getScreenHeight(): Int {
    val size = Point()
    windowManager.defaultDisplay.getSize(size)
    return size.y
}

fun String.onlyDigits(): String = replace(Regex("\\D*"), "")

fun View.showKeyboard(show: Boolean) {
    val imm = context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
    if (show) {
        if (requestFocus()) imm.showSoftInput(this, 0)
    } else {
        imm.hideSoftInputFromWindow(windowToken, 0)
    }
}

/**
 * Loads image with Glide into the [ImageView].
 *
 * @param url url to load
 * @param previousUrl url that already loaded in this target. Needed to prevent white flickering.
 * @param round if set, the image will be round.
 * @param cornersRadius the corner radius to set. Only used if [round] is `false`(by default).
 * @param crop if set to `true` then [CenterCrop] will be used. Default is `false` so [FitCenter] is used.
 */
@SuppressLint("CheckResult")
fun ImageView.load(
    url: String,
    previousUrl: String? = null,
    round: Boolean = false,
    cornersRadius: Int = 0,
    crop: Boolean = false
) {

    val requestOptions = when {
        round -> RequestOptions.circleCropTransform()

        cornersRadius > 0 -> {
            RequestOptions().transforms(
                if (crop) CenterCrop() else FitCenter(),
                RoundedCorners(cornersRadius)
            )
        }

        else -> null
    }

    Glide
        .with(context)
        .load(url)
        .let {
            // Apply request options
            if (requestOptions != null) {
                it.apply(requestOptions)
            } else {
                it
            }
        }
        .let {
            // Workaround for the white flickering.
            // See https://github.com/bumptech/glide/issues/527
            // Thumbnail changes must be the same to catch the memory cache.
            if (previousUrl != null) {
                it.thumbnail(
                    Glide
                        .with(context)
                        .load(previousUrl)
                        .let {
                            // Apply request options
                            if (requestOptions != null) {
                                it.apply(requestOptions)
                            } else {
                                it
                            }
                        }
                )
            } else {
                it
            }
        }
        .into(this)
}

inline fun <reified C : Collection<T>, reified T : Any> Moshi.collectionAdapter(): JsonAdapter<C> {
    val parametrizedType = Types.newParameterizedType(C::class.java, T::class.java)
    return this.adapter<C>(parametrizedType)
}

Thank you

I have a improvement for the withClickableSpan extension, basically if you want search by multiple values.

fun SpannableString.withClickableSpan(pattern: Pattern, onClickListener: (String) -> Unit): SpannableString {

val matcher: Matcher = pattern.matcher(this)

while (matcher.find()) {

    val tag: String = matcher.group(0)
    val clickableSpan = object : ClickableSpan() {
        override fun onClick(widget: View?) = onClickListener.invoke(tag)
    }

    setSpan(clickableSpan, matcher.start(), matcher.end(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
}

return this

}

Even you can use this..

fun TextView.makeLinks(vararg links: Pair<String, View.OnClickListener>) {
    val spannableString = SpannableString(this.text)
    for (link in links) {
        val clickableSpan = object : ClickableSpan() {
            override fun onClick(view: View) {
                Selection.setSelection((view as TextView).text as Spannable, 0)
                view.invalidate()
                link.second.onClick(view)
            }
        }
        val startIndexOfLink = this.text.toString().indexOf(link.first)
        spannableString.setSpan(
            clickableSpan, startIndexOfLink, startIndexOfLink + link.first.length,
            Spanned.SPAN_EXCLUSIVE_EXCLUSIVE
        )
    }
    this.movementMethod =
        LinkMovementMethod.getInstance() // without LinkMovementMethod, link can not click
    this.setText(spannableString, TextView.BufferType.SPANNABLE)
}