Kotlin Useful Extensions

Activity.kt

/**
 * The `fragment` is added to the container view with id `frameId`.
 * The operation is performed by the `fragmentManager`.
 */
fun AppCompatActivity.addFragment(
    fragmentManager: FragmentManager,
    fragment: Fragment,
    frameId: Int) {

  kotlin.checkNotNull(fragmentManager)
  kotlin.checkNotNull(fragment)
  val transaction = fragmentManager.beginTransaction()
  transaction.add(frameId, fragment)
  transaction.commit()
}

/**
 * Activity extension function to hide keyboard
 */
fun AppCompatActivity.hideKeyboard() {
  val imm = getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
  imm.hideSoftInputFromWindow(findViewById(android.R.id.content).getWindowToken(), 0);
}

/**
 * Activity extension function to set full screen activity
 */
fun AppCompatActivity.setFullScreen() {
  requestWindowFeature(Window.FEATURE_NO_TITLE)
  window.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
      WindowManager.LayoutParams.FLAG_FULLSCREEN)
}

Context.kt

/**
 * Context extension to check network available or not.
 */
fun Context.isNetworkConnected(): Boolean {
    val cm = this.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
    val activeNetwork = cm.activeNetworkInfo
    return activeNetwork != null && activeNetwork.isConnectedOrConnecting
}

/**
 * Context extension to inflate the layout.
 */
fun Context.inflateLayout(resource: Int, root: ViewGroup? = null, attachToRoot: Boolean = false): View {
    return LayoutInflater.from(this).inflate(resource, root, attachToRoot)
}

inline fun Context.alert(func: AlertDialog.Builder.() -> AlertDialog.Builder) {
    AlertDialog.Builder(this).func().show()
}

fun Context.toastShort(text: CharSequence) = Toast.makeText(this, text, Toast.LENGTH_SHORT).show()
fun Context.toastShort(resId: Int) = Toast.makeText(this, resId, Toast.LENGTH_SHORT).show()
fun Context.toastLong(text: CharSequence) = Toast.makeText(this, text, Toast.LENGTH_LONG).show()
fun Context.toastLong(resId: Int) = Toast.makeText(this, resId, Toast.LENGTH_LONG).show()

String.kt

fun String.isEmailValid(): Boolean {
  val emailPattern = "^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@" + "[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$"
  val pattern: Pattern = Pattern.compile(emailPattern)
  val matcher: Matcher = pattern.matcher(this)
  return matcher.matches()
}

fun String.upperCaseFirstLetter(): String {
   return this.substring(0, 1).toUpperCase().plus(this.substring(1))
}