Adapter for spinner with hint

SpinnerWithHintAdapter.java

/**
 * @author Vasili Chyrvon ([email protected])
 */
class SpinnerWithHintAdapter(context: Context, @LayoutRes resource: Int, @StringRes hintResId: Int) : ArrayAdapter<String>(context, resource) {

    private val hintColor by lazy { getHintColorAttribute() }
    private var textColors: ColorStateList? = null
    private val hint by lazy { context.getString(hintResId) }

    override fun isEnabled(position: Int): Boolean {
        return if (position == 0) false else super.isEnabled(position)
    }

    override fun getDropDownView(position: Int, convertView: View?, parent: ViewGroup?): View {
        val text = super.getDropDownView(position, convertView, parent) as TextView
        if (textColors == null) textColors = text.textColors // Save default text
        if (position == 0) text.setTextColor(hintColor) else text.setTextColor(textColors)
        return text
    }

    override fun getView(position: Int, convertView: View?, parent: ViewGroup?): View {
        val text = super.getView(position, convertView, parent) as TextView
        if (position == 0) text.setTextColor(hintColor)
        return text
    }

    override fun add(`object`: String?) {
        super.add(`object`)
        if (noHint()) insert(hint, 0)
    }

    override fun addAll(collection: MutableCollection<out String>?) {
        super.addAll(collection)
        if (noHint()) insert(hint, 0)
    }

    override fun addAll(vararg items: String?) {
        super.addAll(*items)
        if (noHint()) insert(hint, 0)
    }

    private fun noHint() = count == 0 || getItem(0) != hint

    override fun clear() {
        super.clear()
        add(hint)
    }

    private fun getHintColorAttribute(): Int {
        val tv = TypedValue()
        context.theme.resolveAttribute(android.R.attr.textColorHint, tv, true)
        return ContextCompat.getColor(context, tv.resourceId)
    }
}