Artem Hluhovskyi hluhovskyi

## medium_2.kt
private lateinit var errorMessage: TextView
…
override fun onCreate(savedInstanceState: Bundle?) {
    …
    errorMessage = findViewById(R.id.error_message) as TextView
}

## medium_1.java
private TextView errorMessage;
…
@Override
protected void onCreate(Bundle savedInstanceState) {
    errorMessage = (TextView) findViewById(R.id.error_message);
}

## medium_3.kt
fun <T : View> Activity.getViewById(@IdRes id: Int): T {
    return findViewById(id) as T
}

## medium_4.kt
private lateinit var errorMessage: TextView
…
override fun onCreate(savedInstanceState: Bundle?) {
    …
    errorMessage = getViewById(R.id.error_message)
}

## medium_5.kt
private val errorMessage: TextView by lazy { getViewById(R.id.error_message) }

## medium_6.kt
class ViewFinderDelegate<T : View> : ReadOnlyProperty<Activity, T> {

    private object EMPTY
    private val id: Int
    private var view: Any? = Empty

    constructor(@IdRes id: Int) {
        this.id = id
    }


## medium_7.kt
private val errorMessage: TextView by ViewFinderDelegate(R.id.error_message)

## medium_8.kt
fun <T : View> Activity.view(IdRes id: Int): ReadOnlyProperty<Activity, T>
    = ViewFinderDelegate(id)

## medium_9.kt
private val errorMessage: TextView by view(R.id.errorMessage)

## medium_10.kt
interface ContextProvdier {
    fun provideContext(): Context
}

class OwnActivity : AppCompatActivity(), ContextProvider {
    fun provideContext() = this
}

class OwnFragment : Fragment(), ContextProvider {
    fun provideContext() = context