ActionScript中的Flex移动按钮外观 - 多行标签显示

Question

我正在开发Flex mobil e应用程序，并且一直在优化其在移动设备上的性能。我已经读过皮肤必须写在ActionScript中，所以我试图创建我的AS ButtonSkin。

public class mButtonSkin extends ButtonSkin
{
    private static var colorMatrix:Matrix = new Matrix();

    protected var radiusX:Number = 12;
    protected var mAngle:Number = 30;
    protected var labelWidth:Number;
    protected var labelHeight:Number;
    protected var paddingLeft:Number = 12;
    protected var paddingRight:Number = 12;
    protected var paddingTop:Number = 2;
    protected var paddingBottom:Number = 2;



    public function mButtonSkin() {
        super();
    }


    override protected function drawBackground(unscaledWidth:Number,unscaledHeight:Number) : void {
        colorMatrix.createGradientBox(width,height,mAngle);
        if (currentState == "up") {
            graphics.beginGradientFill(GradientType.LINEAR, 
                [hostComponent.getStyle("fill3"),hostComponent.getStyle("fill1")], [1,1], [0,255], colorMatrix);
        } else {
            graphics.beginFill(hostComponent.getStyle("fill4"));
        }

        graphics.lineStyle(0.5,hostComponent.getStyle("borderColor"),0.5);
        graphics.drawRoundRect(0,0,hostComponent.width,hostComponent.height,12);
        graphics.endFill();
    }


    override protected function layoutContents(unscaledWidth:Number, unscaledHeight:Number) : void {
        labelDisplay.wordWrap = true;
        labelDisplay.multiline = true;

        labelDisplay.commitStyles();

        labelWidth = width - paddingLeft - paddingRight;
        labelHeight = height - paddingTop - paddingBottom;

        var x:Number = width / 2 - labelWidth / 2;
        var y:Number = height / 2 - getElementPreferredHeight(labelDisplay) / 2;

        setElementSize(labelDisplay,labelWidth,labelHeight);
        setElementPosition(labelDisplay,x,y);
    }


    override protected function labelDisplay_valueCommitHandler(event:FlexEvent) : void {
        labelDisplayShadow.text = "";
    }
}

在我的按钮中应用此皮肤：

按钮labelDisplay的对齐方式错误（verticalAlignment必须为中间）。

点击按钮后：

我的按钮labelDisplay现在垂直对齐到中间。

我错过了什么吗？我做错了什么？

Answer 1

在layoutContents函数上的

，在定位labelDisplay元素之前，我首先检查它的numLines属性是否大于1.这是我的更新函数：

    override protected function layoutContents(unscaledWidth:Number, unscaledHeight:Number) : void {
        labelDisplay.wordWrap = true;
        labelDisplay.multiline = true;

        labelWidth = width - paddingLeft - paddingRight;
        labelHeight = height - paddingTop - paddingBottom;

        var x:Number = width * .5 - labelWidth * .5;
        var y:Number = height * .5 - getElementPreferredHeight(labelDisplay) * .5;

        setElementSize(labelDisplay,labelWidth,labelHeight);

        if (labelDisplay.numLines == 1)
            setElementPosition(labelDisplay,x,y);
        else
            setElementPosition(labelDisplay, x, labelDisplay.getLayoutBoundsY());
    }

这个解决方案可能对其他开发人员没用，但它解决了我的问题。