Container(height: 50,width: MediaQuery.of(context).size.width * 2 / 3,alignment: Alignment.center,child: TextField(autofocus: true,decoration: InputDecoration(//这行代码是关键，设置这个之后，居中contentPadding: EdgeInsets.all(2),hintText: '请输入手机号',prefixIcon: Icon(Icons.phone_android),border: OutlineInputBorder(borderSide: BorderSide(color: Colors.grey[600]),borderRadius: BorderRadius.circular(5),)),style: new TextStyle(color: Colors.black,fontSize: 16,),maxLines: 1,textAlign: TextAlign.left,onChanged: (text) {//内容改变的回调_phoneStr = text;print('change $_phoneStr');},onSubmitted: (text) {//内容提交(按回车)的回调print('submit $text');},),)