Snackbar extensions on Kotlin, to create a useful small DSL.

HomeActivity.kt

class HomeActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_home)
        setSupportActionBar(toolbar)

        fab.setOnClickListener {
            it.snack("Snack message") {
                action("Action") { toast("Action clicked") }
            }
        }
    }
    
}

SnackbarExtensions.kt

inline fun View.snack(@IntegerRes messageRes: Int, length: Int = Snackbar.LENGTH_LONG, f: Snackbar.() -> Unit) {
    snack(resources.getString(messageRes), length, f)
}

inline fun View.snack(message: String, length: Int = Snackbar.LENGTH_LONG, f: Snackbar.() -> Unit) {
    val snack = Snackbar.make(this, message, length)
    snack.f()
    snack.show()
}

fun Snackbar.action(@IntegerRes actionRes: Int, color: Int? = null, listener: (View) -> Unit) {
    action(view.resources.getString(actionRes), color, listener)
}

fun Snackbar.action(action: String, color: Int? = null, listener: (View) -> Unit) {
    setAction(action, listener)
    color?.let { setActionTextColor(color) }
}

Hey, you should replace the @IntegerRes annotations with @StringRes ones.

setActionTextColor needs to use a ColorInt. With the current support library, you can use this:

fun Snackbar.action(action: String, color: Int? = null, listener: (View) -> Unit) {
    setAction(action, listener)
    color?.let { setActionTextColor(ContextCompat.getColor(context, color)) }
}

All changes:

import android.view.View
import androidx.annotation.StringRes
import androidx.core.content.ContextCompat
import com.google.android.material.snackbar.Snackbar

inline fun View.snack(@StringRes messageRes: Int, length: Int = Snackbar.LENGTH_LONG, f: Snackbar.() -> Unit) {
    snack(resources.getString(messageRes), length, f)
}

inline fun View.snack(message: String, length: Int = Snackbar.LENGTH_LONG, f: Snackbar.() -> Unit) {
    val snack = Snackbar.make(this, message, length)
    snack.f()
    snack.show()
}

fun Snackbar.action(@StringRes actionRes: Int, color: Int? = null, listener: (View) -> Unit) {
    action(view.resources.getString(actionRes), color, listener)
}

fun Snackbar.action(action: String, color: Int? = null, listener: (View) -> Unit) {
    setAction(action, listener)
    color?.let { setActionTextColor(ContextCompat.getColor(context, color)) }
}

All changes:

import android.view.View
import androidx.annotation.StringRes
import androidx.core.content.ContextCompat
import com.google.android.material.snackbar.Snackbar

inline fun View.snack(@StringRes messageRes: Int, length: Int = Snackbar.LENGTH_LONG, f: Snackbar.() -> Unit) {
    snack(resources.getString(messageRes), length, f)
}

inline fun View.snack(message: String, length: Int = Snackbar.LENGTH_LONG, f: Snackbar.() -> Unit) {
    val snack = Snackbar.make(this, message, length)
    snack.f()
    snack.show()
}

fun Snackbar.action(@StringRes actionRes: Int, color: Int? = null, listener: (View) -> Unit) {
    action(view.resources.getString(actionRes), color, listener)
}

fun Snackbar.action(action: String, color: Int? = null, listener: (View) -> Unit) {
    setAction(action, listener)
    color?.let { setActionTextColor(ContextCompat.getColor(context, color)) }
}

Thanks @webserveis