Android Activity extensions

Activity.kt

import android.app.Activity
import android.widget.Toast
import android.view.View
import kotlin.properties.Delegates
import android.app.Fragment

fun Activity.toast(s: CharSequence, length: Int = Toast.LENGTH_SHORT) =
        Toast.makeText(this, s, length).show()

fun <T : View?>Activity.find(id: Int) =
        Delegates.lazy { this.findViewById(id) as T }

fun <T> Activity.service(name: String) =
        Delegates.lazy { this.getSystemService(name) as T }

fun Activity.click(id: Int, f: ((View) -> Unit)?) =
        this.findViewById(id)?.setOnClickListener(f)


fun Activity.click(v: View?, f: ((View) -> Unit)?) =
        v?.setOnClickListener(f)


fun Fragment.toast(s: CharSequence, length: Int = Toast.LENGTH_SHORT) =
        getActivity()?.toast(s, length)