解决flex s:TextInput 与输入法兼容的问题
用s:TextArea 代替s:TextInput

<s:TextArea id="infoText" maxChars="30" width="100%" height="23" alpha=".2" />

然后这样取值
var str:String=TextConverter.export(infoText.textFlow,TextConverter.PLAIN_TEXT_FORMAT,ConversionType.STRING_TYPE) as String;
str=StringUtil.trim(str);

完了