ImageButton that is checkable. Supports the state_checked, so that selectors can work seamlessly. MUST put the file attrs.xml in raw/values. Min sdk is 16

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="CheckableImageButton">
        <attr name="android:checked" format="boolean" />
    </declare-styleable>
</resources>

CheckableImageButton.kt

/*
Do whatever u want, I don't care
Arutyun 2020
*/

import android.*
import android.content.*
import android.content.res.*
import android.os.*
import android.util.*
import android.view.*
import android.view.accessibility.*
import android.widget.*
import androidx.appcompat.widget.*
import androidx.core.view.*
import androidx.core.view.accessibility.*

class CheckableImageButton(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : AppCompatImageButton(context, attrs, defStyleAttr), Checkable
{
    private var mChecked = false

    constructor(context: Context) : this(context, null)
    constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, androidx.appcompat.R.attr.imageButtonStyle)

    override fun isChecked() = mChecked
    override fun setChecked(checked: Boolean)
    {
        if (mChecked != checked)
        {
            mChecked = checked
            refreshDrawableState()
            sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED)
        }
    }

    override fun toggle()
    {
        isChecked = !mChecked
    }

    override fun performClick(): Boolean
    {
        toggle()
        return super.performClick()
    }

    override fun onCreateDrawableState(extraSpace: Int): IntArray = if (mChecked)
        mergeDrawableStates(super.onCreateDrawableState(extraSpace + 1), intArrayOf(android.R.attr.state_checked))
    else
        super.onCreateDrawableState(extraSpace)

    override fun onSaveInstanceState() = SavedState(super.onSaveInstanceState()).apply { checked = mChecked }

    override fun onRestoreInstanceState(state: Parcelable)
    {
        if (state !is SavedState)
            super.onRestoreInstanceState(state)
        else
        {
            super.onRestoreInstanceState(state.superState)
            isChecked = state.checked
        }
    }

    class SavedState : BaseSavedState
    {
        var checked = false

        internal constructor(superState: Parcelable?) : super(superState)

        private constructor(`in`: Parcel) : super(`in`)
        {
            checked = `in`.readInt() == 1
        }

        override fun writeToParcel(out: Parcel, flags: Int)
        {
            super.writeToParcel(out, flags)
            out.writeInt(if (checked) 1 else 0)
        }
    }

    init
    {
        val a = context.obtainStyledAttributes(attrs, R.styleable.CheckableImageButton)
        isChecked = a.getBoolean(R.styleable.CheckableImageButton_android_checked, false)
        a.recycle()
        ViewCompat.setAccessibilityDelegate(this, object : AccessibilityDelegateCompat()
        {
            override fun onInitializeAccessibilityEvent(host: View?, event: AccessibilityEvent)
            {
                super.onInitializeAccessibilityEvent(host, event)
                event.isChecked = isChecked
            }

            override fun onInitializeAccessibilityNodeInfo(host: View?, info: AccessibilityNodeInfoCompat)
            {
                super.onInitializeAccessibilityNodeInfo(host, info)
                info.isCheckable = true
                info.isChecked = isChecked
            }
        })
    }
}