ajaypro

Background

Platform-Agnostic

• "Introduction to Bluetooth Low Energy" by Adafruit.

Android-Specific

• "Android Lollipop: Bluetooth LE Matures" - A nice overview video by Dave Smith. Focuses on Lollipop and newer.
• Fragmented Episode 45: "Bluetooth (LE) with Dave (devunwired) Smith" - Another great Dave Smith overview if you prefer the podcast format!

ajaypro

data class Bus(val model:String, val route:Int, val isSpecialService: Boolean)

    val volvo = Bus("volvo", 23, true)
    val leyland = Bus("leyland", 45, false)
    val benz = Bus("benz", 109, true)
    val scania = Bus("scania", 901, false)

/**
 *  Usage of partition and also destructing constructors
 */

ajaypro

//string to date
fun main() {
    
    var str = "2020-05-05"
     val date =   LocalDate.parse(str, DateTimeFormatter.ISO_DATE)
    println(date)
    
}

ajaypro

// replace whitespaces in string
fun main() {
    
    var str = "T    his is b  ett     er."
    var pharse = str.replace("\\s".toRegex(),"")
    println(pharse)
    
}

We've used regular expression \\s that finds all white space characters (tabs, spaces, new line character, etc.) 

ajaypro

fun main() {
   val str = "12345"
    var numeric = false
     numeric =  str.matches("-?\\d+(\\.\\d+)?".toRegex())
     
    if (numeric)
        println("$str is a number")
    else
        println("$str is not a number")
}

ajaypro

    private const val MY_EMAIL = "ajay@[email protected]"
    fun main() {
        val username = MY_EMAIL.substringBeforeLast(delimiter = '@', missingDelimiterValue = "Username not found")
        println("Username -> $username")
    }
    // Output
    Username -> ajay@deepak07
    

ajaypro

    private const val FILE_PATH = "/storage/emulated/0/DCIM/Gallery/.2394823usfdfh234uu9sd2333.mp4"
    fun main() {
        val fileExtension = FILE_PATH.substringAfterLast(delimiter = ".", missingDelimiterValue = "Extension Not found")
        println("File extension -> $fileExtension")
    }
    // Output
    File extension -> mp4
    
    Explanation: the substringAfterLast method successfully gives the file extension 
    although the FILE_PATH contains two delimiter value well, that’s because the method 

ajaypro

    private const val EMAIL = "[email protected]"
    fun main() {
       val username = MY_EMAIL.substringBefore(delimiter = "@", missingDelimiterValue = "Usernmae Not Found")
       println("Username -> $username")
    }
    // Output
    Username -> ajaydeepak07

  Explanation: the above program returns the substring before the appearance of @ character.

ajaypro

    private const val FILE_PATH = "/storage/emulated/0/DCIM/Gallery/erwfwet285d9cesdferqwrsdfsg7e3259f.mp4"
    
    fun main() {
        val extension = FILE_PATH.substringAfter(delimiter = ".", missingDelimiterValue = "Extension Not found")
        println("File extension -> $extension")
    }
    
    // Output
    File extension -> mp4
    

ajaypro

Can be used in data binding

android:text='@{item.title ?? ""}'
android:text='@{imageProperty.copyright ?? ""}'