Construkt

The main goal of this project is to explore the abilities of Kotlin for making DSL of regular Views.

Just playground. Not for prod.

How it looks like

class AppActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            val currentScreen = MutableStateFlow<Screen>(Screen.Home)
            linearLayout(linearLayoutParams().maxSize()) {
                orientation(LinearLayout.VERTICAL)
                linearLayout(linearLayoutParams().maxWidth().weight(1f)) {
                    orientation(LinearLayout.VERTICAL)
                    gravity(Gravity.CENTER)
                    currentScreen.constructOnEach {
                        when (it) {
                            is Screen.Home -> HomeScreen()
                            is Screen.About -> AboutScreen()
                        }
                    }
                }

                bottomNavigationView(linearLayoutParams().maxWidth()) {
                    val color = ColorStateList(android.R.attr.state_checked to Color.WHITE, default = Color.GRAY)
                    itemIconTintList(color)
                    itemTextColor(color)
                    labelVisibilityMode(NavigationBarView.LABEL_VISIBILITY_LABELED)

                    menu {
                        item("Home", id = 1).setIcon(R.drawable.ic_outline_home_24)
                        item("About", id = 2).setIcon(R.drawable.ic_outline_info_24)
                    }

                    onItemSelectedListener {
                        when (it.itemId) {
                            1 -> currentScreen.value = Screen.Home
                            2 -> currentScreen.value = Screen.About
                        }
                        true
                    }
                }
            }
        }
    }
}

Full code here

Generation

Every view except of base interfaces will be generated. So, there is provided an api with ksp to generate such DSL. Using the @ViewDSL annotation, library will generate interface, implementation for interface (to show only api for end user), function that will automatically add view into view hierarchy and extensions.

Example:

@ViewDSL
typealias TextView = android.widget.TextView

Generates:

interface TextView {
    fun text(text: String)
    fun textSize(textSize: Int)
    ...
}

fun ViewGroup.textView(layoutParams: LayoutParams? = null, block: TextView.() -> Unit) {
    addView(TextViewImpl().apply(block))
}

fun ViewGroup.textView(layoutParams: State<LayoutParams>, block: TextView.() -> Unit) {
    addView(TextViewImpl().apply(block))
}

fun TextView.text(text: State<String>) {
    lifecycleOwner.lifecycleScope.launch {
        text.collect { text(it) }
    }
}

fun TextView.textSize(textSize: State<Int>) {
    lifecycleOwner.lifecycleScope.launch {
        textSize.collect { textSize(it) }
    }
}