Kotlin Extension for set/get compound Drawable to TextView/EditText/Button as property

DrawableCompat.kt

/*
 * Copyright 2017 Piruin Panichphol
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
@file:Suppress("NOTHING_TO_INLINE")

import android.app.Fragment
import android.content.Context
import android.graphics.PorterDuff
import android.graphics.drawable.Drawable
import android.os.Build
import android.support.annotation.DrawableRes
import android.view.View
import android.widget.TextView
import org.jetbrains.anko.AnkoContext

fun Context.drawable(@DrawableRes id: Int): Drawable {
    return if (Build.VERSION.SDK_INT >= 21) {
        resources.getDrawable(id, null)
    } else {
        @Suppress("DEPRECATION")
        resources.getDrawable(id)
    }
}

inline fun AnkoContext<*>.drawable(@DrawableRes id: Int) = ctx.drawable(id)
inline fun Fragment.drawable(@DrawableRes id: Int) = activity.drawable(id)
inline fun View.drawable(@DrawableRes id: Int) = context.drawable(id)

fun Drawable.tint(color: Int, mode: PorterDuff.Mode = PorterDuff.Mode.SRC_IN) {
    mutate().setColorFilter(color, mode)
}

var TextView.drawableStart: Drawable?
    get() = drawables[0]
    set(value) = setDrawables(value, drawableTop, drawableEnd, drawableBottom)

var TextView.drawableTop: Drawable?
    get() = drawables[1]
    set(value) = setDrawables(drawableStart, value, drawableEnd, drawableBottom)

var TextView.drawableEnd: Drawable?
    get() = drawables[2]
    set(value) = setDrawables(drawableStart, drawableTop, value, drawableBottom)

var TextView.drawableBottom: Drawable?
    get() = drawables[3]
    set(value) = setDrawables(drawableStart, drawableTop, drawableEnd, value)

@Deprecated("Consider replace with drawableStart to better support right-to-left Layout", ReplaceWith("drawableStart"))
var TextView.drawableLeft: Drawable?
    get() = compoundDrawables[0]
    set(value) = setCompoundDrawablesWithIntrinsicBounds(value, drawableTop, drawableRight, drawableBottom)

@Deprecated("Consider replace with drawableEnd to better support right-to-left Layout", ReplaceWith("drawableEnd"))
var TextView.drawableRight: Drawable?
    get() = compoundDrawables[2]
    set(value) = setCompoundDrawablesWithIntrinsicBounds(drawableLeft, drawableTop, value, drawableBottom)

private val TextView.drawables: Array<Drawable?>
    get() = if (Build.VERSION.SDK_INT >= 17) compoundDrawablesRelative else compoundDrawables

private fun TextView.setDrawables(start: Drawable?, top: Drawable?, end: Drawable?, buttom: Drawable?) {
    if (Build.VERSION.SDK_INT >= 17)
        setCompoundDrawablesRelativeWithIntrinsicBounds(start, top, end, buttom)
    else
        setCompoundDrawablesWithIntrinsicBounds(start, top, end, buttom)
}

ExampleActivity.kt

class ExampleActivity : AppCompatActivity() {

  override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_example)

      addButton.drawableStart = drawable(R.drawable.ic_add_white_24px)
      addButton.drawableStart  = drawable(R.drawable.ic_add_white_24px).apply { tint(Color.BLACK) }
  }
}

Firstly, I create this extension because on Pre-Lollipop, we can't set plain vector drawables as compound drawables (drawableStart/Top/End/Bottom) at layout .xml file.

As my opinion, It better to set plain-vector-drawable programmatically than unnecessarily wrap it with drawable container such as a StateListDrawable, InsetDrawable .

Update : error on Pre-Lollipop occur by set
vectorDrawables.useSupportLibrary = true
without that line we can set vector drawable at xml directly

import org.jetbrains.anko.AnkoContext
this is unavailable in android studio 3.0.1 , so i can not use this method :
inline fun AnkoContext<*>.drawable(@DrawableRes id: Int) = ctx.drawable(id)