Anko is a library that reduces boilerplate code in Android development using Kotlin. It has four main parts: Anko Commons, Anko Layouts, Anko SQLite, and Anko Coroutines. Anko Commons simplifies tasks like creating intents and dialogs. Anko Layouts allows defining UI with a DSL instead of XML for type safety and null safety. Anko SQLite helps with database operations. Anko Coroutines integrates coroutines into Android. The presentation compares code samples with and without Anko to demonstrate how it reduces boilerplate. It also discusses using AnkoComponents to define custom UI elements and keep the code separated.

1. Anko & Karamba
in Kotlin Bapusaheb Patil
Google-certified Android
Developer & OpenClassrooms
Android Mentor
www.bapspatil.com

2. My sample app for this talk:
Ankara
bit.do/baps-ankara

3. What is Anko?

4. What We Know:
Kotlin reduces boilerplate
(lengthy) code in Android
Development, when compared
with Java.

5. Anko, if used in Kotlin,
reduces boilerplate code
even further.
What We Need To Know:

6. + A bunch of other super
useful stuff I’ll be
covering in this talk

7. 4 Parts of Anko
• Anko Commons
• Anko Layouts
• Anko SQLite
• Anko Coroutines

8. Setting up Anko...
App-level build.gradle file:
kotlin {
experimental {
coroutines “enable”
}
}
dependencies {
implementation “org.jetbrains.anko:anko:0.10.4”
}

9. Anko Commons
Usage of Intents:
INTENTS WITHOUT ANKO
val intent = Intent(this, SomeActivity::class.java)
intent.putExtra("id", 13)
startActivity(intent)

10. Anko Commons
Usage of Intents:
INTENTS WITH ANKO
startActivity<SomeActivity>("id" to 13)

11. Anko Commons
Usage of Intents:
BROWSER INTENT WITHOUT ANKO
val uri =
Uri.parse(“https://www.bapspatil.com”)
val browserIntent = Intent(Intent.ACTION_VIEW,
uri)
startActivity(browserIntent)

12. Anko Commons
Usage of Intents:
BROWSER INTENT WITH ANKO
browse(“https://www.bapspatil.com”)

13. Anko Commons
Usage of Intents:
CALL INTENT WITHOUT ANKO
val uri = Uri.parse(“tel:+917788990099”)
val callIntent = Intent(Intent.ACTION_DIAL)
callIntent.data = uri
startActivity(callIntent)

14. Anko Commons
Usage of Intents:
CALL INTENT WITH ANKO
makeCall(“+917788990099”)

15. Anko Commons
Usage of Common Android Components:
TOAST WITHOUT ANKO
Toast.makeText(context,
“Hello, people of BlrKotlin!”,
Toast.LENGTH_SHORT)
.show()

16. Anko Commons
Usage of Common Android Components:
TOAST WITH ANKO
toast(“Hello, people of BlrKotlin!”)
// longToast(“Hello, people of BlrKotlin!”)

17. Anko Commons
Usage of Common Android Components:
SNACKBAR WITHOUT ANKO
val snackbar = Snackbar.make(view,
“Hello, people of BlrKotlin!”,
Snackbar.LENGTH_SHORT)
.setAction ( “HI!”,
{ v ->
doSomething()
})
snackbar.show()

18. Anko Commons
Usage of Common Android Components:
SNACKBAR WITH ANKO
snackbar(view, “Hello, people of BlrKotlin!”, “HI!”){
doSomething()
}

19. Anko Commons
Usage of Common Android Components:
ALERTDIALOG WITHOUT ANKO
var alertDialog = AlertDialog.Builder(this)
.setMessage("Hi, this is a message for the AlertDialog.")
.setTitle("Title of the AlertDialog")
.setPositiveButton("OK", DialogInterface.OnClickListener { dialog,
which ->
doSomethingPositive()
})
.setNegativeButton("Cancel", DialogInterface.OnClickListener {
dialog, which ->
doSomethingNegative()
})
.create()
.show()

20. Anko Commons
Usage of Common Android Components:
ALERTDIALOG WITH ANKO
alert(“Hi, this is a message for the AlertDialog.”, “Title of
the AlertDialog”) {
yesButton { doSomethingPositive() }
noButton { doSomethingNegative() }
}.show()

21. Anko Commons
Usage of Logging:
LOGGING WITHOUT ANKO
Log.v(“MainActivity”, “This activity was
created successfully!”)

22. Anko Commons
Usage of Logging:
LOGGING WITH ANKO
class MainActivity : AppCompatActivity(),
AnkoLogger {
override fun onCreate(savedInstanceState:
Bundle?) {
verbose(“This activity was created
successfully!”)
}
}

23. Anko
Layouts

24. But what’s wrong with XML?
• It forces you to write the same code again.
• It is not typesafe.
• It is not null-safe.
• No code reuse.
• XML parsing is too much overhead. Takes too much CPU time,
and hence battery.

25. But what’s wrong with XML?

26. Why not create the UI programmatically?

27. Why not create the UI programmatically?
Because...it looks ugly. Here’s an example:
val activity = this
val layout = LinearLayout(activity)
layout.orientation = LinearLayout.VERTICAL
val nameEditText = EditText(activity)
val button = Button(activity)
button.text = “Hey There!"
button.setOnClickListener {
Toast.makeText(activity, "Hello there, ${nameEditText.text}!",
Toast.LENGTH_SHORT).show()
}
layout.addView(nameEditText)
layout.addView(button)

28. All that code...
...just for this?

29. Enter,
Anko Layouts.

30. Anko Layouts
MainActivity.kt
override fun onCreate(savedState: Bundle?) {
super.onCreate(savedState)
verticalLayout {
val nameEditText = editText()
button(“Hey There!”) {
onClick {
toast(“Hello there, ${nameEditText.text}!”)
}
}
}
}

31. This makes Virat
happy too.

32. Let’s take a
closer look at
Anko Layouts...

33. Attributes in Anko Layouts DSL
verticalLayout {
lparams(width = matchParent, height = matchParent)
textView {
id = R.id.helloTextView
text = “Hello, people of BlrKotlin!”
textSize = 32f
textColor = 0xffffff.opaque
padding = dip(16)
gravity = Gravity.START // gravity in XML
}.lparams(width = wrapContent, height = wrapContent) {
gravity = Gravity.CENTER // layout_gravity in XML
margin = dip(4)
}
}

34. AnkoComponent<T>
What is it & why use it?
- It’s a separate class where you can write your DSL code for your UI.
- It is reusable.
- It keeps the UI separate from logic.
- You can convert existing XML files to AnkoComponents with the Anko
Support plugin.
- You also get a layout preview if you install the Anko Support plugin.

35. Keep UI code in a separate file!

36. AnkoComponent<T>
MainView.kt
class MainView : AnkoComponent<MainActivity> {
override fun createView(ui: AnkoContext<MainActivity>):
View = with(ui) {
verticalLayout {
...
...
...
}
}
}

37. AnkoComponent<T>
MainActivity.kt
class MainActivity : AppCompatActivity() {
lateinit val textView: TextView
override fun onCreate(savedState: Bundle?) {
super.onCreate(savedState)
MainView().setContentView(this)
textView = find(R.id.helloTextView)
toast(textView.text)
}
}

38. Still not convinced about Anko
Layouts?
• 1 parent RelativeLayout
▪ 17 ImageViews
▪ 1 SurfaceView
▪ 2 TextViews
▪ 1 View

39. Just visit the Wiki at https://bit.do/anko-constraint

40. Anko
Coroutines
•asReference()
•bg()

41. asReference()
MainActivity.kt
...
val ref: Ref<MainActivity> = this.asReference()
doAsync {
uiThread {
ref().updateUI()
}
}
...

42. bg()
MainActivity.kt
...
val ref: Ref<MainActivity> = this.asReference()
doAsync {
val someData = bg { getDataThatTakesLongTimeToFetch() }
uiThread {
ref().updateUI(someData.await())
}
}
...

43. Karamba
A small bunch of useful Kotlin extensions,
very similar to Anko Commons.
https://bit.do/karamba-kotlin
by matteocrippa

44. How would you convert a View to a
Bitmap?
val returnedBitmap = Bitmap.createBitmap(view.width,
view.height,Bitmap.Config.ARGB_8888)
val canvas = Canvas(returnedBitmap)
val bgDrawable = view.background
if (bgDrawable != null)
bgDrawable.draw(canvas)
else
canvas.drawColor(Color.WHITE)
view.draw(canvas)
return returnedBitmap

45. How would you convert a View to a
Bitmap?
val returnedBitmap = view.toBitmap()

46. How would you resize a Bitmap?
val scaleWidth = newWidth.toFloat() / oldWidth
val scaleHeight = newHeight.toFloat() / oldHeight
val matrix = Matrix()
matrix.postScale(scaleWidth, scaleHeight)
val resizedBitmap = Bitmap.createBitmap(
this, 0, 0, oldWidth, oldHeight, matrix, false)
resizedBitmap.recycle()
return resizedBitmap

47. How would you resize a Bitmap?
val resizedBitmap = oldBitmap.resize(newWidth, newHeight)

48. There’s a ton of stuff...
API VERSION:
• support(apiVersion)
• supportLollipop()
• supportKitkat()
BITMAP:
• base64()
• resize(width, height)
BOOLEAN:
• toggle()
• random()
DATE:
• convertTo(format)
[Eg:format=“dd-MM-yy”]
• toCalendar()
• isFuture()
• today()
DOUBLE:
• localCurrency(currency)
[Eg:currency=“USD”]
• celsiusToFahrenheit()
INTEGER:
• commaSeparatedId()
• readableDistanceFromMe
ters()
STRING:
• isValidEmail()
• isPhoneNumber()
• plainText()
• toBitmap()
VIEW:
• toBitmap()
+ more extension functions can be found at
https://bit.do/karamba-kotlin

50. Thank you.
Bapusaheb Patil
Google-certified Android
Developer & OpenClassrooms
Android Mentor
www.bapspatil.com
GitHub | github.com/bapspatil
LinkedIn | linkedin.com/in/bapspatil
Pinterest | pinterest.com/bapspatil
Twitter | twitter.com/baps_patil
(couldn’t get @bapspatil for this one! ☹)
Play Store | bit.do/bapsapps
Watchfaces | bit.do/bapswat