compound view parent

CompoundView.kt

import android.annotation.TargetApi
import android.content.Context
import android.graphics.Outline
import android.os.Build
import android.support.constraint.ConstraintLayout
import android.util.AttributeSet
import android.view.View
import android.view.ViewOutlineProvider


/**
 * class for compound views
 */
abstract class CompoundView : ConstraintLayout {
    constructor(context: Context) : super(context) {
        initLayout()
    }

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

    constructor(context: Context,
                attrs: AttributeSet,
                defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
        initLayout()
        loadAttrs(attrs)
    }


    /**
     * // usual content:
     * val a = context.obtainStyledAttributes(attrs, R.styleable.IconLabel, 0, 0)

        val t = a.getString(R.styleable.IconLabel_a_label)
        if (t != null) textView!!.text = t

        val im = a.getDrawable(R.styleable.IconLabel_a_icon)
        if (im != null) icon!!.setImageDrawable(im)

        a.recycle()
     */
    abstract fun loadAttrs(attrs: AttributeSet)

    /**
     * // usual content:
     * val inflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
        inflater.inflate(R.layout.w_action_item, this)

        textView = this.v_label as TextView
        icon = this.v_icon
     */
    abstract fun initLayout()

    /**
     * elevation support for compound views
     */
    override fun onSizeChanged(w: Int,
                               h: Int,
                               oldw: Int,
                               oldh: Int) {
        super.onSizeChanged(w, h, oldw, oldh)
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            outlineProvider = CustomOutline(w, h)
        }
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    private inner class CustomOutline internal constructor(internal var width: Int,
                                                           internal var height: Int) : ViewOutlineProvider() {

        override fun getOutline(view: View,
                                outline: Outline) {
            outline.setRect(0, 0, view.width, view.height)
        }
    }
}