FloatingActionButton to simulate Material design look

dimens-sw600dp.xml

<dimen name="fab_size">96dp</dimen>
<dimen name="fab_icon_size">32dp</dimen>

dimens-sw720dp.xml

<dimen name="fab_size">144dp</dimen>
<dimen name="fab_icon_size">48dp</dimen>

dimens.xml

<dimen name="fab_size">72dp</dimen>
<dimen name="fab_icon_size">24dp</dimen>

FloatingActionButton.java

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.DecelerateInterpolator;
import android.view.animation.OvershootInterpolator;

import com.dgsd.android.shiftminer.R;
import com.dgsd.android.shiftminer.util.UiUtils;

public class FloatingActionButton extends View {

    private Paint mShadowPaint;

    private Paint mDrawablePaint;
    private Bitmap mBitmap;

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

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

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

    {
        setExpandOnTouch(true);
        setLayerType(LAYER_TYPE_SOFTWARE, null);

        setWillNotDraw(false);
        mShadowPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mShadowPaint.setStyle(Paint.Style.FILL);
        mShadowPaint.setShadowLayer(10.0f, 0.0f, 3.5f, Color.argb(100, 0, 0, 0));
        mDrawablePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        final int w = getWidth();
        final int h = getHeight();

        canvas.drawCircle(w / 2, h / 2, w / 2.6f, mShadowPaint);
        if (mBitmap != null) {
            canvas.drawBitmap(mBitmap,
                    (w - mBitmap.getWidth()) / 2, (h - mBitmap.getHeight()) / 2, mDrawablePaint);
        }
    }

    public void setExpandOnTouch(boolean expand) {
        setOnTouchListener(expand ? new FabTouchListener() : null);
    }

    public void setFloatingActionIcon(final int iconRes) {
        UiUtils.onPreDraw(this, new Runnable() {
            @Override
            public void run() {
                final Resources r = getResources();
                final int viewSize = Math.min(getWidth(), getHeight());
                final int idealIconSize = r.getDimensionPixelSize(R.dimen.fab_icon_size);

                final int iconSize = viewSize == 0 ? idealIconSize :
                        Math.min(viewSize, idealIconSize);

                final Bitmap bm = BitmapFactory.decodeResource(r, iconRes);
                final BitmapDrawable iconDrawable = new BitmapDrawable(r, Bitmap.createScaledBitmap(
                        bm, iconSize, iconSize, true));

                mBitmap = iconDrawable.getBitmap();
                invalidate();
            }
        });
    }

    public void setFloatingActionColor(int color) {
        mShadowPaint.setColor(color);
        invalidate();
    }

    private static class FabTouchListener implements OnTouchListener {

        private static final int BOUNCH_DURATION = 100;

        private static final DecelerateInterpolator mDecelerateInterpolator
                = new DecelerateInterpolator();
        private static final OvershootInterpolator mOvershootInterpolator
                = new OvershootInterpolator(10);

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            if (event.getAction() == MotionEvent.ACTION_DOWN) {
                v.animate().setInterpolator(mDecelerateInterpolator)
                        .scaleX(1.15f).scaleY(1.15f).setDuration(BOUNCH_DURATION);
            } else if (event.getAction() == MotionEvent.ACTION_UP) {
                v.animate().setInterpolator(mOvershootInterpolator)
                        .scaleX(1f).scaleY(1f).setDuration(BOUNCH_DURATION);
            }

            return false;
        }
    }
}