kotlin handsome code 集合

Kotlin custom constructor ways

thanks: 
https://medium.com/@rygel/stop-repeating-yourself-and-create-custom-views-on-android-with-kotlin-f5b3fc581c0e
https://medium.com/@elye.project/building-custom-component-with-kotlin-fc082678b080
https://medium.com/@mmlodawski/https-medium-com-mmlodawski-do-not-always-trust-jvmoverloads-5251f1ad2cfe
1.
constructor(context: Context) : super(context) {
    init(context)
}

constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
    init(context)
}

constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
    init(context)
}

2.

@JvmOverloads
constructor(context: Context,
            attrs: AttributeSet? = null,
            defStyleAttr: Int = 0
) : super(context, attrs, defStyleAttr)

@TargetApi(Build.VERSION_CODES.LOLLIPOP)
constructor(context: Context,
            attrs: AttributeSet?,
            defStyleAttr: Int,
            defStyleRes: Int
) : super(context, attrs, defStyleAttr, defStyleRes)