PopupContainerWithArrow.java 文件源码

/**
 * Adds an arrow view pointing at the original icon.
 * @param horizontalOffset the horizontal offset of the arrow, so that it
 *                              points at the center of the original icon
 */
private View addArrowView(int horizontalOffset, int verticalOffset, int width, int height) {
    LayoutParams layoutParams = new LayoutParams(width, height);
    if (mIsLeftAligned) {
        layoutParams.gravity = Gravity.START;
        layoutParams.leftMargin = horizontalOffset;
    } else {
        layoutParams.gravity = Gravity.END;
        layoutParams.rightMargin = horizontalOffset;
    }
    if (mIsAboveIcon) {
        layoutParams.topMargin = verticalOffset;
    } else {
        layoutParams.bottomMargin = verticalOffset;
    }

    View arrowView = new View(getContext());
    if (Gravity.isVertical(((FrameLayout.LayoutParams) getLayoutParams()).gravity)) {
        // This is only true if there wasn't room for the container next to the icon,
        // so we centered it instead. In that case we don't want to show the arrow.
        arrowView.setVisibility(INVISIBLE);
    } else {
        ShapeDrawable arrowDrawable = new ShapeDrawable(TriangleShape.create(
                width, height, !mIsAboveIcon));
        Paint arrowPaint = arrowDrawable.getPaint();
        // Note that we have to use getChildAt() instead of getItemViewAt(),
        // since the latter expects the arrow which hasn't been added yet.
        PopupItemView itemAttachedToArrow = (PopupItemView)
                (getChildAt(mIsAboveIcon ? getChildCount() - 1 : 0));
        arrowPaint.setColor(itemAttachedToArrow.getArrowColor(mIsAboveIcon));
        // The corner path effect won't be reflected in the shadow, but shouldn't be noticeable.
        int radius = getResources().getDimensionPixelSize(R.dimen.popup_arrow_corner_radius);
        arrowPaint.setPathEffect(new CornerPathEffect(radius));
        arrowView.setBackground(arrowDrawable);
        arrowView.setElevation(getElevation());
    }
    addView(arrowView, mIsAboveIcon ? getChildCount() : 0, layoutParams);
    return arrowView;
}