/**
     * 相对anchor view显示，适用 宽高不为match_parent
     * <p>
     * 注意：如果使用 VerticalGravity 和 HorizontalGravity 时，请确保使用之后 PopupWindow 没有超出屏幕边界，
     * 如果超出屏幕边界，VerticalGravity 和 HorizontalGravity 可能无效，从而达不到你想要的效果。
     *
     * @param anchor
     * @param vertGravity  垂直方向的对齐方式
     * @param horizGravity 水平方向的对齐方式
     * @param x            水平方向的偏移
     * @param y            垂直方向的偏移
     */
    public void showAtAnchorView(@NonNull View anchor, @YGravity final int vertGravity, @XGravity int horizGravity, int x, int y) {
        //防止忘记调用 apply() 方法
        checkIsApply(true);

        mAnchorView = anchor;
        mOffsetX = x;
        mOffsetY = y;
        mYGravity = vertGravity;
        mXGravity = horizGravity;
        //处理背景变暗
        handleBackgroundDim();
        x = calculateX(anchor, horizGravity, mWidth, mOffsetX);
        y = calculateY(anchor, vertGravity, mHeight, mOffsetY);
        //是否重新获取宽高
        if (isNeedReMeasureWH) {
            registerOnGlobalLayoutListener();
        }
//        Log.i(TAG, "showAtAnchorView: w=" + measuredW + ",y=" + measuredH);
        PopupWindowCompat.showAsDropDown(mPopupWindow, anchor, x, y, Gravity.NO_GRAVITY);

    }
 

@RequiresApi(api = Build.VERSION_CODES.KITKAT)
public void showAsDropDown(View anchor, int offsetX, int offsetY, int gravity) {
    //防止忘记调用 apply() 方法
    checkIsApply(false);

    handleBackgroundDim();
    mAnchorView = anchor;
    mOffsetX = offsetX;
    mOffsetY = offsetY;
    //是否重新获取宽高
    if (isNeedReMeasureWH) {
        registerOnGlobalLayoutListener();
    }
    PopupWindowCompat.showAsDropDown(mPopupWindow, anchor, mOffsetX, mOffsetY, gravity);
}
 

@Override public void onClick(View v) {
    if (clickListener != null) {
        clickListener.onClick(v);
    }
    //using 8dip on axisX offset to make dropdown view visually be at start of dropdown itself
    //using 4dip on axisY offset to make space between dropdown view and dropdown itself
    //all offsets are necessary because of the dialog_holo_light_frame to display correctly on screen(shadow was made by inset)
    int gravity;
    int axisXOffset;
    if (dropDownViewWidth + getX() > screenWidth) {
        gravity = Gravity.TOP | Gravity.END;
        axisXOffset = DimenUtils.dpToPixels(8);
    }
    else {
        gravity = Gravity.TOP | Gravity.START;
        axisXOffset = -DimenUtils.dpToPixels(8);
    }
    int axisYOffset = DimenUtils.dpToPixels(4);
    switch (expandDirection) {
        case UP:
            PopupWindowCompat.showAsDropDown(dropdownWindow, v,
                    axisXOffset,
                    -dropDownViewHeight - getMeasuredHeight() - axisYOffset * 3,
                    gravity);
            break;
        case DOWN:
            PopupWindowCompat.showAsDropDown(dropdownWindow, v,
                    axisXOffset,
                    -axisYOffset,
                    gravity);
            break;
    }
    setSelected(true);
}
 

/**
 * Show at relative position to anchor View with translation.
 * @param anchor Anchor View
 * @param vertPos Vertical Position Flag
 * @param horizPos Horizontal Position Flag
 * @param x Translation X
 * @param y Translation Y
 * @param fitInScreen Automatically fit in screen or not
 */
public void showOnAnchor(@NonNull View anchor, @VerticalPosition int vertPos, @HorizontalPosition int horizPos, int x, int y, boolean fitInScreen) {
    setClippingEnabled(fitInScreen);
    View contentView = getContentView();
    contentView.measure(makeDropDownMeasureSpec(getWidth()), makeDropDownMeasureSpec(getHeight()));
    final int measuredW = contentView.getMeasuredWidth();
    final int measuredH = contentView.getMeasuredHeight();
    if (!fitInScreen) {
        final int[] anchorLocation = new int[2];
        anchor.getLocationInWindow(anchorLocation);
        x += anchorLocation[0];
        y += anchorLocation[1] + anchor.getHeight();
    }
    ViewGroup.MarginLayoutParams anchorLP = (ViewGroup.MarginLayoutParams) anchor.getLayoutParams();
    switch (vertPos) {
        case VerticalPosition.ABOVE:
            y -= measuredH + anchor.getHeight() + anchorLP.topMargin;
            break;
        case VerticalPosition.ALIGN_BOTTOM:
            y -= measuredH;
            break;
        case VerticalPosition.CENTER:
            y -= anchor.getHeight()/2 + measuredH/2;
            break;
        case VerticalPosition.ALIGN_TOP:
            y -= anchor.getHeight();
            break;
        case VerticalPosition.BELOW:
            y += anchorLP.topMargin;
            break;
        default:
            break;
    }
    switch (horizPos) {
        case HorizontalPosition.LEFT:
            x -= measuredW + anchorLP.leftMargin;
            break;
        case HorizontalPosition.ALIGN_RIGHT:
            x -= measuredW - anchor.getWidth();
            break;
        case HorizontalPosition.CENTER:
            x += anchor.getWidth()/2 - measuredW/2;
            break;
        case HorizontalPosition.ALIGN_LEFT:
            // Default position.
            break;
        case HorizontalPosition.RIGHT:
            x += anchor.getWidth() + anchorLP.rightMargin;
            break;
        default:
            break;
    }
    if (fitInScreen) {
        PopupWindowCompat.showAsDropDown(this, anchor, x, y, Gravity.NO_GRAVITY);
    } else {
        showAtLocation(anchor, Gravity.NO_GRAVITY, x, y);
    }
}