FloatingActionButton with custom ripple colours

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="FloatingActionButton">
        <attr name="backgroundColor" format="color" />
        <attr name="highlightColor" format="color" />
    </declare-styleable>
</resources>

dimens.xml

<resources>
    <dimen name="fab_elevation">3dp</dimen>
    <dimen name="fab_press_translation_z">2dp</dimen>
</resources>

fab_elevation.xml

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_enabled="true" android:state_pressed="true">
        <set>
            <objectAnimator android:duration="@android:integer/config_shortAnimTime"
                android:propertyName="translationZ"
                android:valueTo="@dimen/fab_press_translation_z"
                android:valueType="floatType"/>
        </set>
    </item>
    <item>
        <set>
            <objectAnimator android:duration="@android:integer/config_shortAnimTime"
                android:propertyName="translationZ"
                android:valueTo="0"
                android:valueType="floatType"/>
        </set>
    </item>
</selector>

FloatingActionButton.java

package com.marianeum.fab;

import android.animation.AnimatorInflater;
import android.content.Context;
import android.content.res.ColorStateList;
import android.content.res.TypedArray;
import android.graphics.Outline;
import android.graphics.drawable.GradientDrawable;
import android.graphics.drawable.RippleDrawable;
import android.util.AttributeSet;
import android.widget.ImageButton;

import com.marianeum.fab.R;

public class FloatingActionButton extends ImageButton {

    private final Outline outline = new Outline();

    public FloatingActionButton(Context context) {
        super(context);
        init(context, null, 0, 0);
    }

    public FloatingActionButton(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs, 0, 0);
    }

    public FloatingActionButton(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(context, attrs, defStyleAttr, 0);
    }

    public FloatingActionButton(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        init(context, attrs, defStyleAttr, defStyleRes);
    }

    private void init(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        ColorStateList backgroundColor = null;
        ColorStateList highlightColor = null;

        if (attrs != null) {
            TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.FloatingActionButton, defStyleAttr, defStyleRes);
            try {
                backgroundColor = ta.getColorStateList(R.styleable.FloatingActionButton_backgroundColor);
                highlightColor = ta.getColorStateList(R.styleable.FloatingActionButton_highlightColor);
            } finally {
                ta.recycle();
            }
        }
        
        if (backgroundColor == null) {
            backgroundColor = new ColorStateList(new int[][]{new int[]{0}}, new int[]{getResources().getColor(R.color.accent)});
        }

        if (highlightColor == null) {
            highlightColor = new ColorStateList(new int[][]{new int[]{0}}, new int[]{getResources().getColor(R.color.accent_highlight)});
        }

        GradientDrawable background = new GradientDrawable();
        background.setShape(GradientDrawable.OVAL);
        background.setColor(backgroundColor);

        RippleDrawable rippleDrawable = new RippleDrawable(background, null);
        rippleDrawable.setColor(highlightColor);
        setBackground(rippleDrawable);
        
        if (getElevation() == 0) {
            setElevation(getResources().getDimension(R.dimen.fab_elevation));
        }
        
        if (getStateListAnimator() == null) {
            setStateListAnimator(AnimatorInflater.loadStateListAnimator(getContext(), R.anim.fab_elevation));
        }
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);

        outline.setOval(0, 0, w, h);
        setOutline(outline);
    }
}

@INRIX-Iurii-Okhmat can you point out the tweaking?