kotan library

Easy koding for Android with kotlin language

Currently author uses it only in his own projects. But any contributions, ideas and requests are welcome.

Integration

Thanks to JitPack it's easy to include kotan dependency to your project

Add following lines to your gradle build file:

repositories {
    . . . .
    maven { url 'https://jitpack.io' }
}

dependencies {
    . . . .
    implementation 'com.github.ruXlab:kotan:-SNAPSHOT'
}

Find view

Can be done by using delegate: LazyView

public open class BaseActivity : Activity() {
    private val myName by LazyView<TextView>(R.id.mainMyName)
    private val bermudaButton by LazyView<Button?>(R.id.mainBermudaButton)
}

If view might exists(i.e. optional)_ in layout you have to make it nullable like TextView?, ListView?, etc. This delegate will work for following type of UI components:

• Activity. It must be accessed after setContentView()
• Fragment. I would recommend to return inflated layout in onCreateView() and start working with layout in following lifecycle methods such as onActivityCreated()
• View. It's possible to access to UI components anywhere in your code after the inflation process finished(if any).

View events binding

Main concept of UI event handling is registering callbacks via functions started with on, such as onClick or onLongClick

public open class BaseActivity : Activity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContentView(R.layout.main)

        bermudaButton?.onClick {
            myName.setText("Place your name here")
        }
    }
}

ListView

List item click handler:

    list.onItemClick<Fruit> { fruit ->
        // process chosen fruit
    }

SharedProperties / Settings

Working with SharedPreferences is awful I hope you know it. Lets use power of kotlin to make work with settings as simple as we work with variables

• Let's declare our persistent preferences storage. Just subclass Preferences providing any Context reference and name of preferences

  class Configuration(context: Context): Preferences(context, "cfg") {
      var sheepCounter by IntValue(0)
      var myName by StringValue("moo")
  }

  Currently available: StringValue, IntValue, LongValue, FloatValue

• Then, create instance of this preferences and use it just generic class:

  public open class BaseActivity : Activity() {
      val cfg = Configuration(this)
  
      override fun onCreate(savedInstanceState: Bundle?) {
          super.onCreate(savedInstanceState)
  
          setContentView(R.layout.main)
  
          bermudaButton?.onClick {
              cfg.sheepCounter++
              cfg.myName = "${cfg.myName} moo"
              myName.setText(cfg.myName)
          }
      }
  }

Broadcast messages handling

Android have very powerful broadcast messaging mechanism but down the road it's always unhandy.

Kotan will help you to use in very easy way

• Describe entities you going to send, as well your broadcast events. Remember your entities must implement Serializable

  object NEW_MESSAGE: Broadcast<ChatMessage>()
  object DATABASE_UPDATED: Broadcast<DatabaseDetails>()
  object COFFEE_READY: Broadcast<Coffee>()

• Send it.

  COFFEE_READY.sendBroadcast(context, Coffee("latte"))

• Receive it. Don't forget to register your receiver

  class CoffeeActivity: Activity() {
      val coffeeReceiver = COFFEE_READY.broadcastReceiver(this) { coffee ->
          toastLong("Your ${coffee.name} is ready to drink, sir")
      }
  
      override fun onStart() {
          super.onStart()
          coffeeReceiver.register(this)
      }
  
      override fun onStop() {
          super.onStop()
          coffeeReceiver.unregister(this)
      }
  }

View manipulation

// TODO