Unable to get exact circle shape when using card view

Question

I\'m using card view for floating action button in android material design. I\'m using following code for get the circle

Answer 1

card_layout.xml

MainActivity.java

 ImageView imageView = (ImageView) findViewById(R.id.card_thumbnail_image);
    Bitmap mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.rose);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP){
        //Default 
        imageView.setBackgroundResource(R.drawable.rose);
    } else {
        //RoundCorners 
        RoundCornersDrawable round = new RoundCornersDrawable(mBitmap,
                getResources().getDimension(R.dimen.cardview_default_radius), 0); //or your custom radius

        CardView cardView = (CardView) findViewById(R.id.card_view);
        cardView.setPreventCornerOverlap(false); //it is very important

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
            imageView.setBackground(round);
        else
            imageView.setBackgroundDrawable(round);
    }

RoundCornersDrawable.java

    public class RoundCornersDrawable extends Drawable {

    private final float mCornerRadius;
    private final RectF mRect = new RectF();
    //private final RectF mRectBottomR = new RectF();
    //private final RectF mRectBottomL = new RectF();
    private final BitmapShader mBitmapShader;
    private final Paint mPaint;
    private final int mMargin;

    public RoundCornersDrawable(Bitmap bitmap, float cornerRadius, int margin) {
        mCornerRadius = cornerRadius;

        mBitmapShader = new BitmapShader(bitmap,
                Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);

        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setShader(mBitmapShader);

        mMargin = margin;
    }

    @Override
    protected void onBoundsChange(Rect bounds) {
        super.onBoundsChange(bounds);
        mRect.set(mMargin, mMargin, bounds.width() - mMargin, bounds.height() - mMargin);
        //mRectBottomR.set( (bounds.width() -mMargin) / 2, (bounds.height() -mMargin)/ 2,bounds.width() - mMargin, bounds.height() - mMargin);
       // mRectBottomL.set( 0,  (bounds.height() -mMargin) / 2, (bounds.width() -mMargin)/ 2, bounds.height() - mMargin);
    }

    @Override
    public void draw(Canvas canvas) {
        canvas.drawRoundRect(mRect, mCornerRadius, mCornerRadius, mPaint);
        //canvas.drawRect(mRectBottomR, mPaint); //only bottom-right corner not rounded
        //canvas.drawRect(mRectBottomL, mPaint); //only bottom-left corner not rounded

    }

    @Override
    public int getOpacity() {
        return PixelFormat.TRANSLUCENT;
    }

    @Override
    public void setAlpha(int alpha) {
        mPaint.setAlpha(alpha);
    }

    @Override
    public void setColorFilter(ColorFilter cf) {
        mPaint.setColorFilter(cf);
    }


}