CardView has extra margin in each edge on Pre-Lollipop

Question

Here are two pictures.

on Lollipop:

on Pre-Lollipop:

Answer 1

To solve the "shadow space" issue for PRE-L versions, you can dynamically update the CardView margin by negative values to compensate the space.

To get the actual shadow space:

shadowSpaceLeft = getPaddingLeft() - getContentPaddingLeft();

To fix the margin:

layoutParams.leftMargin -= shadowSpaceLeft;

This will work for all Android versions since we are getting the padding values and the contentPadding values dynamically.

For example, here is a class that does it whenever we set new layout params:

public class NoPaddingCardView extends CardView {

    public NoPaddingCardView(Context context) {
        super(context);
        init();
    }

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

    public NoPaddingCardView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        // Optional: Prevent pre-L from adding inner card padding 
        setPreventCornerOverlap(false);
        // Optional: make Lollipop and above add shadow padding to match pre-L padding
        setUseCompatPadding(true);
    }

    @Override
    public void setLayoutParams(ViewGroup.LayoutParams params) {
        // FIX shadow padding
        if (params instanceof MarginLayoutParams) {
            MarginLayoutParams layoutParams = (MarginLayoutParams) params;
            layoutParams.bottomMargin -= (getPaddingBottom() - getContentPaddingBottom());
            layoutParams.leftMargin -= (getPaddingLeft() - getContentPaddingLeft());
            layoutParams.rightMargin -= (getPaddingRight() - getContentPaddingRight());
            layoutParams.topMargin -= (getPaddingTop() - getContentPaddingTop());
        }

        super.setLayoutParams(params);
    }
}