Flex 打印常使用PrintDataGrid，但会有一些问题，不支持表格单元格合并，有的可能需要打印一些flex组件和容器（VBox, HBox, Text, Image）等。重写flex的Grid表格，Grid类似HTML的table, 能很好支持单元格合并，单元格中加入组件和容器。

自定义PrintDataGrid：

public class PrintDataGrid extends Grid
    {
       public static const pageHeight:int = 1023;
 
       private var _realWidth:int;
 
       public function PrintDataGrid()
       {
           this.horizontalScrollPolicy = ScrollPolicy.OFF;
           this.verticalScrollPolicy = ScrollPolicy.OFF;
 
           super();
       }
 
       public function addGridRow(gridRow:RowGrid):void {
           addCells(gridRow.getAvailableCell(), gridRow.height);
       }
 
       private function addCells(cells:Array, height:Number):void {
           var gridRow:GridRow = new GridRow();
           for each(var cell:GridCell in cells) {
              gridRow.addChild(cell);
           }
           gridRow.height = height;
           this.addChild(gridRow);
       }
 
       public function get realWidth():int
       {
           return _realWidth;
       }
 
       public function set realWidth(value:int):void
       {
           _realWidth = value;
       }
    }

Adobe对于多页打印或打印预览都没有提供一个很好的解决办法，但可以根据Grid中GridRow的height,计算自动拆分表格，将一个大的Grid拆分每一个页面一个Grid，进行分页预览和打印。大概的算法：根据每页的height值计算一个页面能存放多少Grid的GridRow，超过的拆分到下一个页面，如果需要拆分的单元格存在被合并的情况，也就是GridItem 中RowSpan > 1, 则需要将一个GridItem，分为两个GridItem，而这两个的GridItem的rowSpan之和为原来的GridItem的RowSpan。


合并单元格拆分：

public function splitRowSpan(gridCellArray:GridCellArray):void {
           if(cells.length == 0) {
               return;
           }
           for(var i:int = 0; i < cells.length; i++) {
              var gridCell:GridCell = cells[i] as GridCell;
              if(gridCell == null) {
                  continue;
              }
              var splitCell:GridCell = null;
              if (gridCell.isRemove) {
                  splitCell = gridCell.mergerCell;
              }
              if (splitCell == null) {
                  continue;
              }
              if (gridCell.rNum == splitCell.rNum) {
                  continue;
              }
              var orgRowSpan:int = splitCell.rowSpan;
              var extRowSpan:int = gridCell.rNum - splitCell.rNum;
             
              var content:DisplayObject = splitCell.getChildAt(0);
             
              var topCellHeight:Number = getExtRowSpanHeight(splitCell.rNum, splitCell.rNum + extRowSpan, gridCellArray);
              var bottomCellHeight:Number = getExtRowSpanHeight(splitCell.rNum + extRowSpan, splitCell.rNum + splitCell.rowSpan, gridCellArray);
             
              splitCell.rowSpan = extRowSpan;
              splitCell.height = topCellHeight;
              if(topCellHeight < bottomCellHeight) {
                  splitCell.removeAllChildren();
              }
             
              var  bottomCell:GridCell = splitCell.newGridCell();
              bottomCell.rowSpan = orgRowSpan - extRowSpan;
              bottomCell.colSpan = splitCell.colSpan;
              bottomCell.height = bottomCellHeight;
              bottomCell.rNum = gridCell.rNum;
              bottomCell.cNum = gridCell.cNum;
              if(topCellHeight < bottomCellHeight) {
                  bottomCell.addChild(content);
              }
             
              var gridRow:RowGrid = gridCellArray.getRowGrid(gridCell.rNum);
              gridRow.setCell(bottomCell, bottomCell.cNum);
              if (bottomCell.rowSpan > 1 || bottomCell.colSpan > 1) {
                  gridCellArray.mergerGridCell(bottomCell);
              }
           }
       }


原文出处: http://www.anyrt.com/blog/list/201609131739.html