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

<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 2

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 3

use

shape = "ring"

use same layout_height and layout_weight

and

app:cardCornerRadius= half of layout_height or layout_weight

example

<android.support.v7.widget.CardView
                        android:id="@+id/cardview"
                        android:layout_width="110dp"
                        android:layout_height="110dp"
                        android:shape="ring"
                        app:cardCornerRadius="55dp">
</android.support.v7.widget.CardView>

Answer 4

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 5

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.
        }
     }