Flex中如何通过maxChars属性，限制TextArea控件中允许输入的字数

main.mxml

1. <?xml version="1.0" encoding="utf-8"?>
2. <mx:Applicationxmlns:mx="http://www.adobe.com/2006/mxml"
3. layout="vertical"
4. verticalAlign="middle"
5. backgroundColor="white">
7. <mx:Script>
8. <![CDATA[
9. private function textArea_change(evt:Event):void {
10. var ta:TextArea = evt.currentTarget as TextArea;
11. progressBar.setProgress(ta.length, ta.maxChars);
12. }
14. private function progressBar_progress(evt:ProgressEvent):void {
15. var pb:ProgressBar = evt.currentTarget as ProgressBar;
16. if (pb.percentComplete > 95) {
17. pb.setStyle("themeColor", "red");
18. } else if (pb.percentComplete > 80) {
19. pb.setStyle("themeColor", "yellow");
20. } else {
21. pb.setStyle("themeColor", "haloGreen");
22. }
23. }
24. ]]>
25. </mx:Script>
27. <mx:Panel>
28. <mx:TextAreaid="textArea"
29. width="320"
30. height="120"
31. maxChars="300"
32. change="textArea_change(event);"/>
33. <mx:ControlBar>
34. <mx:ProgressBarid="progressBar"
35. mode="manual"
36. minimum="0"
37. maximum="{textArea.maxChars}"
38. label="%1 of %2 characters (%3%%)"
39. labelPlacement="center"
40. width="100%"
41. progress="progressBar_progress(event);"/>
42. </mx:ControlBar>
43. </mx:Panel>
45. </mx:Application>