一个发送验证码的需求:包括限制文本框输入长度和只允许输入数字

按惯例 先上图:

class MyBody extends StatefulWidget { @override _MyBodyState createState() => _MyBodyState();} class _MyBodyState extends State<MyBody> { bool isButtonEnable=true; //按钮状态 是否可点击 String buttonText='发送验证码'; //初始文本 int count=60; //初始倒计时时间 Timer timer; //倒计时的计时器 TextEditingController mController=TextEditingController(); void _buttonClickListen(){ setState(() { if(isButtonEnable){ //当按钮可点击时 isButtonEnable=false; //按钮状态标记 _initTimer(); return null; //返回null按钮禁止点击 }else{ //当按钮不可点击时// debugPrint('false'); return null; //返回null按钮禁止点击 } }); } void _initTimer(){ timer = new Timer.periodic(Duration(seconds: 1), (Timer timer) { count--; setState(() { if(count==0){ timer.cancel(); //倒计时结束取消定时器 isButtonEnable=true; //按钮可点击 count=60; //重置时间 buttonText='发送验证码'; //重置按钮文本 }else{ buttonText='重新发送($count)'; //更新文本内容 } }); }); } @override void dispose() { timer?.cancel(); //销毁计时器 timer=null; super.dispose(); } @override Widget build(BuildContext context) { return Container( child: Column(// mainAxisAlignment: MainAxisAlignment.center, children: <Widget>[ Container( color: Colors.white, padding: EdgeInsets.only(left: 10,right: 10), child: Row( mainAxisAlignment: MainAxisAlignment.spaceBetween,// crossAxisAlignment: CrossAxisAlignment.center, crossAxisAlignment: CrossAxisAlignment.baseline, textBaseline: TextBaseline.ideographic, children: <Widget>[ Text('验证码',style: TextStyle(fontSize: 13,color: Color(0xff333333)),), Expanded( child: Padding(padding: EdgeInsets.only(left: 15,right: 15,top: 15), child: TextFormField( maxLines: 1, onSaved: (value) { }, controller: mController, textAlign: TextAlign.left, inputFormatters: [WhitelistingTextInputFormatter.digitsOnly,LengthLimitingTextInputFormatter(6)], decoration: InputDecoration( hintText: ('填写验证码'), contentPadding: EdgeInsets.only(top: -5,bottom: 0), hintStyle: TextStyle( color: Color(0xff999999), fontSize: 13, ), alignLabelWithHint: true, border: OutlineInputBorder(borderSide: BorderSide.none), ), ),), ), Container( width: 120, child: FlatButton( disabledColor: Colors.grey.withOpacity(0.1), //按钮禁用时的颜色 disabledTextColor: Colors.white, //按钮禁用时的文本颜色 textColor:isButtonEnable?Colors.white:Colors.black.withOpacity(0.2), //文本颜色 color: isButtonEnable?Color(0xff44c5fe):Colors.grey.withOpacity(0.1), //按钮的颜色 splashColor: isButtonEnable?Colors.white.withOpacity(0.1):Colors.transparent, shape: StadiumBorder(side: BorderSide.none), onPressed: (){ setState(() { _buttonClickListen(); });},// child: Text('重新发送 (${secondSy})'), child: Text('$buttonText',style: TextStyle(fontSize: 13,),), ), ), ], ), ), Container( width: double.infinity, height: 45, margin: EdgeInsets.only(top: 50,left: 10,right: 10), child: RaisedButton( onPressed: () { debugPrint('${mController.text}'); }, shape: StadiumBorder(side: BorderSide.none), color: Color(0xff44c5fe), child: Text( '下一步', style: TextStyle(color: Colors.white,fontSize: 15), ), ), ), ], ), ); }}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。