adobeflowlayout.as

flex的一些小例子

/*
Copyright (c) 2007 FlexLib Contributors.  See:
    http://code.google.com/p/flexlib/wiki/ProjectContributors

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

package flexlib.containers.utilityClasses
{
import flash.display.DisplayObject;
import mx.containers.utilityClasses.Layout;
import mx.controls.VRule;
import mx.core.Container;
import mx.core.EdgeMetrics;
import mx.core.IUIComponent;
import mx.core.mx_internal;

import mx.core.UIComponent;

use namespace mx_internal;

[ExcludeClass]

/**
 *  @private
 *  The FlowLayout class is for internal use only.
 */
public class AdobeFlowLayout extends Layout
{
	//--------------------------------------------------------------------------
	//
	//  Constructor
	//
	//--------------------------------------------------------------------------

	/**
	 *  Constructor.
	 */
	public function AdobeFlowLayout()
	{
		super();
	}

	//--------------------------------------------------------------------------
	//
	//  Variables
	//
	//--------------------------------------------------------------------------

	private var lastWidth:int;

	mx_internal var explicitHeightSet:Boolean = false;

	mx_internal var explicitMeasuredHeight:int = 0;

	mx_internal var modifyTargetHeight:Boolean = false;

	mx_internal var rowCount:int = -1;

	/**
	 *  @private
	 *  For future use
	 */
	//private var direction:String = FlowDirection.HORIZONTAL;
	
	//--------------------------------------------------------------------------
	//
	//  Overridden methods
	//
	//--------------------------------------------------------------------------
	
	/**
	 *  @private
	 *  Measure container as per Flow layout rules.
	 */
	override public function measure():void
	{
		var target:Container = Container(super.target);

		var minWidth:Number = 0;
		var minHeight:Number = 0;

		var preferredWidth:Number = 0;
		var preferredHeight:Number = 0;

		var n:int = target.numChildren;
		var numGaps:int = -1;
		for (var i:int = 0; i < n; i++)
		{
			var child:IUIComponent = IUIComponent(target.getChildAt(i));
			if (!child.includeInLayout)
				continue;

			numGaps++;
			var wPref:Number = child.getExplicitOrMeasuredWidth();
			var hPref:Number = child.getExplicitOrMeasuredHeight();

			minWidth = Math.max(minWidth, child.minWidth);
			minHeight = Math.max(minHeight, hPref);
			preferredWidth += wPref;
		}

		var vm:EdgeMetrics = target.viewMetricsAndPadding;
		var wPadding:Number = vm.left + vm.right + numGaps*target.getStyle("horizontalGap");
		var hPadding:Number = vm.top + vm.bottom;

		target.measuredMinWidth = minWidth + wPadding;
		target.measuredMinHeight = minHeight + hPadding;

		if (rowCount > 1)
			target.measuredWidth = preferredWidth / rowCount + wPadding + minWidth;
		else
			target.measuredWidth = preferredWidth + wPadding;
		
		target.measuredHeight = minHeight + hPadding;

		if (explicitMeasuredHeight)
			target.measuredMinHeight = target.measuredHeight = explicitMeasuredHeight;
	}

	/**
	 *  @private
	 *  Lay out children as per Flow layout rules.
	 */
	override public function updateDisplayList(unscaledWidth:Number,
											   unscaledHeight:Number):void
	{
		var target:Container = Container(super.target);

		var vm:EdgeMetrics = target.viewMetricsAndPadding;
		
		var horizontalGap:Number = target.getStyle("horizontalGap");
		var verticalGap:Number = target.getStyle("verticalGap");
       
		var xPos:Number = vm.left;
		var yPos:Number = vm.top;
		var maxYPos:Number = 0;
		
		var n:int = target.numChildren;
		var child:IUIComponent;
		var lastChild:IUIComponent;
		var childWidth:int;
		var childHeight:int;
		var popupIndex:int = 0;
		var xEnd:Number = unscaledWidth - vm.right;
		var full:Boolean = false;
		var remainingRows:int = 0xFFFF;
		
		var xWrapWidth:int = 0xFFFF;
		
		if (rowCount > 0 && target.parent)
		{
			var numLines:int = target.parent.height / target.measuredHeight;
			xWrapWidth = target.measuredWidth / rowCount;
			remainingRows = rowCount - 1;
		}
		for (var i:int = 0; i < target.numChildren; i++)
		{
			child = IUIComponent(target.getChildAt(i));

			if (!child.includeInLayout)
				continue;

			childWidth = child.getExplicitOrMeasuredWidth();
			childHeight = child.getExplicitOrMeasuredHeight();
			
			if(!full)
			{
				// Start a new row?
				if (((xPos + childWidth > xEnd && xPos != vm.left) ||
					xPos > xWrapWidth) && remainingRows)
				{
					yPos = maxYPos + verticalGap;
					remainingRows--;
					xPos = vm.left;

					if (child is VRule)
					{
						child.setActualSize(0, 0);
						child.move(xPos, yPos);
						continue;
					}
					else if (lastChild is VRule)
						lastChild.setActualSize(0, 0);
				}
			}
			
			child.setActualSize(childWidth, childHeight)
			child.move(xPos, yPos);
			lastChild = child;
			maxYPos = Math.max(maxYPos, yPos + childHeight);
			xPos += (childWidth + horizontalGap);
			
		}
			
		maxYPos += vm.bottom;

		if (target.height != maxYPos && isNaN(target.percentHeight) && !explicitHeightSet)
		{
			if (modifyTargetHeight)
			{
				target.height = maxYPos;
			}
			else
			{
				explicitMeasuredHeight = target.measuredHeight = maxYPos;
				target.height = NaN;
			}
			explicitHeightSet = false;
			
			if (lastWidth != unscaledWidth)
			{
				target.callLater(target.invalidateDisplayList);
				lastWidth = unscaledWidth;
			}
		}
	}

}

}