Based on CommonsWare's AspectLockedFrameLayout

AspectLockedCardView.java

package az.dgtl.egg.ui.widget;

import android.content.Context;
import android.support.v7.widget.CardView;
import android.util.AttributeSet;
import android.view.View;

/**
 * Based on CommonsWare's AspectLockedFrameLayout
 */
public final class AspectLockedCardView extends CardView {
    private double aspectRatio = 0.0;
    private AspectRatioSource aspectRatioSource = null;

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

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

    @Override
    protected void onMeasure(int widthSpec, int heightSpec) {
        double localRatio = aspectRatio;

        if (localRatio == 0.0 && aspectRatioSource != null
                && aspectRatioSource.getHeight() > 0) {
            localRatio =
                    (double) aspectRatioSource.getWidth()
                            / (double) aspectRatioSource.getHeight();
        }

        if (localRatio == 0.0) {
            super.onMeasure(widthSpec, heightSpec);
        } else {
            int lockedWidth = MeasureSpec.getSize(widthSpec);
            int lockedHeight = MeasureSpec.getSize(heightSpec);

            if (lockedWidth == 0 && lockedHeight == 0) {
                throw new IllegalArgumentException(
                        "Both width and height cannot be zero -- watch out for scrollable containers");
            }

            // Get the padding of the border background.
            int hPadding = getPaddingLeft() + getPaddingRight();
            int vPadding = getPaddingTop() + getPaddingBottom();

            // Resize the preview frame with correct aspect ratio.
            lockedWidth -= hPadding;
            lockedHeight -= vPadding;

            if (lockedHeight > 0 && (lockedWidth > lockedHeight * localRatio)) {
                lockedWidth = (int) (lockedHeight * localRatio + .5);
            } else {
                lockedHeight = (int) (lockedWidth / localRatio + .5);
            }

            // Add the padding of the border.
            lockedWidth += hPadding;
            lockedHeight += vPadding;

            // Ask children to follow the new preview dimension.
            super.onMeasure(MeasureSpec.makeMeasureSpec(lockedWidth, MeasureSpec.EXACTLY),
                    MeasureSpec.makeMeasureSpec(lockedHeight, MeasureSpec.EXACTLY));
        }
    }

    public void setAspectRatioSource(View v) {
        this.aspectRatioSource = new ViewAspectRatioSource(v);
    }

    public void setAspectRatioSource(AspectRatioSource aspectRatioSource) {
        this.aspectRatioSource = aspectRatioSource;
    }

    // from com.android.camera.PreviewFrameLayout, with slight
    // modifications

    public void setAspectRatio(double aspectRatio) {
        if (aspectRatio <= 0.0) {
            throw new IllegalArgumentException("aspect ratio must be positive");
        }

        if (this.aspectRatio != aspectRatio) {
            this.aspectRatio = aspectRatio;
            requestLayout();
        }
    }

    public interface AspectRatioSource {
        int getWidth();

        int getHeight();
    }

    private static class ViewAspectRatioSource implements AspectRatioSource {
        private View v = null;

        ViewAspectRatioSource(View v) {
            this.v = v;
        }

        @Override public int getWidth() {
            return (v.getWidth());
        }

        @Override public int getHeight() {
            return (v.getHeight());
        }
    }
}