lib-manipulation/src/main/java/com/nhaarman/listviewanimations/itemmanipulation/swipedismiss/undo/SwipeUndoView.java
void setPrimaryView(@NonNull final View primaryView) {
        if (mPrimaryView != null) {
            removeView(mPrimaryView);
        }
        mPrimaryView = primaryView;
        addView(mPrimaryView);
    }
void setPrimaryView(@NonNull final View primaryView) {
        if (mPrimaryView != null) {
            removeView(mPrimaryView);
        }
        mPrimaryView = primaryView;
        addView(mPrimaryView);
    }
Sets the primary {@link android.view.View}. Removes any existing primary {@code View} if present.