如何在TextArea组件中获取插入符号的X,Y坐标?

时间:2011-03-04 03:25:30

标签: flex actionscript-3

我用Google搜索了近一天的时间来找到我的问题的答案,并在polygeek找到了答案:

http://polygeek.com/1826_flex_monitoring-the-position-of-the-cursor-in-a-textarea

这几乎可行(并且是一个很好的解决方案),但是当我这样做时解决方案不起作用: 1)。复制并粘贴多行文本 2)。写长并滚动文本。

我还发现了另一个工作示例: http://www.victordramba.com/?p=31 (当您在插入符号的位置按ctrl +空格时,会出现自动完成提示) 但是其作者的电子邮件(Victor Dramba)说他使用单色字体来计算个人角色的位置,并且没有多大帮助。

有没有办法从文本字段中获取多行输入?

2 个答案:

答案 0 :(得分:3)

我写过这个Helper类,它可以解决你的问题(如果你使用Flex 4):

public class TextAreaHelper
{
    public static function getCaretPosition(ta : TextArea) : Point
    {
        var flowComposer : StandardFlowComposer = StandardFlowComposer(ta.textFlow.flowComposer);
        var absoluteIndex : int = ta.selectionActivePosition;

        var lineIdx : int = flowComposer.findLineIndexAtPosition(absoluteIndex);
        if (lineIdx == flowComposer.numLines)
            lineIdx--;
        var prevLine : TextFlowLine = lineIdx != 0 ? flowComposer.getLineAt(lineIdx - 1) : null;
        var nextLine : TextFlowLine = lineIdx != flowComposer.numLines-1 ? flowComposer.getLineAt(lineIdx + 1) : null

        var result : Rectangle = flowComposer.getLineAt(lineIdx).computePointSelectionRectangle(absoluteIndex, ta, prevLine, nextLine, true);
        if (result)
        {
            var point : Point = new Point(result.x, result.y);
            point.x -= ta.scroller.viewport.horizontalScrollPosition;               
            point.y -= ta.scroller.viewport.verticalScrollPosition;
            return point;
        }
        return null;
    }
}

public class TextAreaHelper { public static function getCaretPosition(ta : TextArea) : Point { var flowComposer : StandardFlowComposer = StandardFlowComposer(ta.textFlow.flowComposer); var absoluteIndex : int = ta.selectionActivePosition; var lineIdx : int = flowComposer.findLineIndexAtPosition(absoluteIndex); if (lineIdx == flowComposer.numLines) lineIdx--; var prevLine : TextFlowLine = lineIdx != 0 ? flowComposer.getLineAt(lineIdx - 1) : null; var nextLine : TextFlowLine = lineIdx != flowComposer.numLines-1 ? flowComposer.getLineAt(lineIdx + 1) : null var result : Rectangle = flowComposer.getLineAt(lineIdx).computePointSelectionRectangle(absoluteIndex, ta, prevLine, nextLine, true); if (result) { var point : Point = new Point(result.x, result.y); point.x -= ta.scroller.viewport.horizontalScrollPosition; point.y -= ta.scroller.viewport.verticalScrollPosition; return point; } return null; } }

以下是一个使用示例:

:<fx:Script>
    <![CDATA[
        [Bindable]
        private var caretPosition : Point;
        private function textareaSelectionChangeHandler(e : FlexEvent) : void
        {
            updateCaretPosition();
        }
        private function onPossibleScrollPositionChange(e : PropertyChangeEvent) : void
        {
            if (["verticalScrollPosition", "horizontalScrollPosition"].indexOf(e.property) != -1)
            {
                updateCaretPosition();
            }
        }
        private function updateCaretPosition() : void
        {
            caretPosition = TextAreaHelper.getCaretPosition(ta);
            if (caretPosition) caretPosition = ta.localToGlobal(caretPosition);
            trace(ObjectUtil.toString(caretPosition));
        }

        private function initTextArea() : void
        {
            ta.addEventListener(FlexEvent.SELECTION_CHANGE, textareaSelectionChangeHandler);
            ta.textDisplay.addEventListener(PropertyChangeEvent.PROPERTY_CHANGE, onPossibleScrollPositionChange);
        }

    ]]>
</fx:Script>
<s:TextArea x="200" y="300" id="ta" creationComplete="initTextArea()" />

<s:Rect x="{caretPosition.x}" y="{caretPosition.y}" width="10" height="10" visible="{caretPosition != null}">
    <s:fill>
        <s:SolidColor color="yellow" />
    </s:fill>
</s:Rect>

答案 1 :(得分:1)

这是单一方式,标签字符标记为一个字符......

public class TextAreaEx extends TextArea 
{       
    ...     

        public function getCaretPosition() : Point
        {
            var pos : int = selectionActivePosition;
            var tx:String = text;
            var p:Point = new Point(pos+1, 1);
            for(var i:int=pos-1; i>0; i--) 
            {
                if (tx.charAt(i) == '\n') 
                {
                    if (p.y==1)
                        p.x = pos-i;
                    p.y++;
                }
            }
            return p;
        }       

}