Android Material Floating Action Button (Supports API 14+ with shadows and 21+ with Lollipop elevation)

FloatingActionButton.java

package com.bigoven.android.widgets;

import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.ShapeDrawable;
import android.graphics.drawable.shapes.OvalShape;
import android.os.Build;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.AccelerateInterpolator;
import android.widget.ImageButton;

import com.bigoven.android.R;
import com.bigoven.android.utilities.UiHelper;


@SuppressLint("ClickableViewAccessibility")
/**
 *  This class is a custom view that encompasses the functionality of Google's Material Design "Floating Action Button"
 *  It supports API 14+ devices.
 *
 *  Copyright (C) 2015 Chantell Osejo
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>
 */
public class FloatingActionButton extends ImageButton {
    public static final int GOOGLE_DESIGN_GUIDELINE_RECOMMENDED_DIAMETER_PX = UiHelper.convertDpToPixel(56);
    public static final int GOOGLE_DESIGN_GUIDELINE_RECOMMENDED_MINI_DIAMETER_PX = UiHelper.convertDpToPixel(40);

    final static AccelerateInterpolator accelerateInterpolator = new AccelerateInterpolator();

    private Paint mBackgroundPaint;
    private int mColor = Color.WHITE;
    private int visibility = View.VISIBLE;
    private ShapeDrawable mCircleBackground;

    public FloatingActionButton(Context context) {
        super(context);
        init();
    }

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

        TypedArray a = context.getTheme().obtainStyledAttributes(
                attrs,
                R.styleable.FloatingActionButton,
                0, 0);

        try {
            mColor = a.getColor(R.styleable.FloatingActionButton_buttonColor, Color.WHITE);
        } finally {
            a.recycle();
        }

        init();
    }

    private void init() {
        setColor(mColor);
        setScaleType(ScaleType.CENTER_INSIDE);
        visibility = getVisibility();
    }

    public void setColor(int color) {
        this.mColor = color;

        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
            setLayerType(LAYER_TYPE_SOFTWARE, mBackgroundPaint);
            mBackgroundPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
            mBackgroundPaint.setColor(mColor);
            mBackgroundPaint.setShadowLayer(10.0f, 0.0f, 3.5f, Color.argb(100, 0, 0, 0));
            setBackgroundDrawable(null);
        } else {
            if (null == mCircleBackground) {
                mCircleBackground = new ShapeDrawable(new OvalShape());
                setBackground(mCircleBackground);
                setElevation(UiHelper.convertDpToPixel(8));
            }

            mCircleBackground.getPaint().setColor(color);
        }

        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
            canvas.drawCircle(getWidth() / 2, getHeight() / 2, (float) (getWidth() / 2.6), mBackgroundPaint);
        }

        super.onDraw(canvas);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_UP) {
            setAlpha(1.0f);
        } else if (event.getAction() == MotionEvent.ACTION_DOWN) {
            setAlpha(0.6f);
        }
        return super.onTouchEvent(event);
    }

    public void setVisibilityAfterDelay(final int visibility, long delay) {
        if (this.visibility == visibility) {
            return;
        }

        this.visibility = visibility;

        boolean hide = this.visibility != View.VISIBLE;

        ObjectAnimator scaleX = ObjectAnimator.ofFloat(this, SCALE_X, hide ? 1 : 0, hide ? 0 : 1);
        ObjectAnimator scaleY = ObjectAnimator.ofFloat(this, SCALE_Y, hide ? 1 : 0, hide ? 0 : 1);
        ObjectAnimator alpha = ObjectAnimator.ofFloat(this, ALPHA, hide ? 1 : 0, hide ? 0 : 1);
        ObjectAnimator rotate = ObjectAnimator.ofFloat(this, ROTATION, 0f, 360f);

        final AnimatorSet animSetXY = new AnimatorSet();
        animSetXY.playTogether(scaleX, scaleY, rotate, alpha);
        animSetXY.setInterpolator(accelerateInterpolator);
        animSetXY.setDuration(hide ? 200 : 300);
        animSetXY.setStartDelay(delay);
        animSetXY.start();
    }

    @Override
    /**
     * Hijacking the visibility parameter to animate hiding/showing the button
     */
    public void setVisibility(final int visibility) {
        setVisibilityAfterDelay(visibility, 0);
    }

    static public class Builder {
        private final Context context;
        int color = Color.WHITE;
        private Drawable drawable;

        /**
         * Builder of the fab button
         *
         * @param context should be an Activity context, used to create the view
         */
        public Builder(Context context) {
            this.context = context;
        }

        /**
         * Sets the FAB drawable
         */
        public Builder setDrawable(final Drawable drawable) {
            this.drawable = drawable;
            return this;
        }

        /**
         * Sets the FAB color
         */
        public Builder setColor(final int color) {
            this.color = color;
            return this;
        }

        public FloatingActionButton create() {
            final FloatingActionButton button = new FloatingActionButton(context);
            button.setColor(this.color);
            button.setImageDrawable(this.drawable);
            return button;
        }
    }
}

    <RelativeLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent">

          <FrameLayout
              android:id="@+id/container"
              android:layout_width="match_parent"
              android:layout_height="match_parent" />

          <com.bigoven.android.widgets.FloatingActionButton
              android:id="@+id/test_fab"
              android:layout_alignParentBottom="true"
              android:layout_alignParentRight="true"
              android:layout_alignParentEnd="true"
              android:layout_width="56dp"
              android:layout_height="56dp"
              android:src="@drawable/ic_add_white_24dp"
              app:buttonColor="@color/big_oven_red_accent"
              android:scaleType="centerInside"
              android:layout_marginRight="16dp"
              android:layout_marginEnd="16dp"
              android:layout_marginBottom="16dp"/>
     </RelativeLayout>

Also, don't forget...in your attrs.xml :

<declare-styleable name="FloatingActionButton">
    <attr name="buttonColor" format="color"/>
</declare-styleable>