Unable to get exact circle shape when using card v

Question

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

<android.support.v7.widget.CardView
    android:id="@+id/fab"
    android:layout_width="38dp"
    android:layout_height="38dp"
    android:layout_marginBottom="10dp"
    android:layout_marginRight="10dp"
    card_view:background="@color/blue"
    card_view:cardCornerRadius="19dp"
    card_view:cardPreventCornerOverlap = "false"
    card_view:cardElevation="6dp" >
</android.support.v7.widget.CardView>

I have set corner radius as half of width. but still I can't get the circle shape.

Answer 1

Yes, I have achieved it by reducing half of the CardCornerRadius to its View's Height.

Answer 2

I have solved the problem. Now android providing design library for material design, which has the FloatingActionButton. No need of customizing card view for floating action button.

<android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"  />

Add design library in gradle dependencies

compile 'com.android.support:design:23.1.1'

For more detail refer this link

Answer 3

card_layout.xml

<android.support.v7.widget.CardView
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:id="@+id/card_view"
    android:layout_gravity="center"
    android:layout_width="250dp"
    android:layout_height="200dp">

    <ImageView
        android:id="@+id/card_thumbnail_image"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        style="@style/card_thumbnail_image"/>
</android.support.v7.widget.CardView>

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);
    }


}

Answer 4

first import the drawbleToolBox library in your project. with this library, you can create drawable dynamically.

for make your cardview circle your radius must be half of its height/widht.

                int radius = cardView.getHeight()/2;
                Drawable drawable = new DrawableBuilder()
                    .rectangle()
                    .solidColor(0xffffffff)

                    .topRightRadius(radius) // in pixels
                    .bottomRightRadius(radius)
                     //otherplaces
                    .build();



                holder.cardView.setBackground(drawable);

if you are using cardview in your recycleview, getting the cardview widths doesn't work becuse it doesn't create yet. so you should do as below

holder.cardView.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener()
    {
        @Override
        public boolean onPreDraw()
        {
         //codes here.
        }
     }

Answer 5

To achieve a circular shape using Card view you can set the shape property, android:shape="ring".
app:cardCornerRadius should be set to half the width or height of the child view

<android.support.v7.widget.CardView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:innerRadius="0dp"
        android:shape="ring"
        app:cardCornerRadius="75dp">

        <ImageView
            android:layout_width="150dp"
            android:layout_height="150dp"
            android:layout_gravity="center"
            android:background="@drawable/image" />
     </android.support.v7.widget.CardView>

Answer 6

I came up with simple Solution of Using a Drawable and it looks amazing!

Get Drawable here https://drive.google.com/open?id=0B4Vo_ku-aIKzUFFnUjYxYVRLaGc