这里是关于如何添加数字键盘，如何进行验证，如何添加样式，以及dart/flutter中的其他内容的所有细节。 我希望它能帮助你更好地学习。

Padding(
            padding: const EdgeInsets.all(3.0),
            child: TextFormField(
              maxLength: 10,
              keyboardType: TextInputType.number,
              validator: (value) {
                if (value.isEmpty) {
                  return 'Enter Number Please';
                }
                
                return null;
              },
              decoration: InputDecoration(
                prefixIcon: Icon(Icons.smartphone),
                prefixText: '+92',
                labelText: 'Enter Phone Number',
                contentPadding: EdgeInsets.zero,
                enabledBorder: OutlineInputBorder(),
                focusedBorder: OutlineInputBorder(
                    borderSide: BorderSide(
                      width: 2, color: Theme
                        .of(context)
                        .primaryColor,
                    )
                ),
                focusColor: Theme
                    .of(context)
                    .primaryColor,
              ),
            ),
          ),

如果需要使用双位数:

keyboardType: TextInputType.numberWithOptions(decimal: true),
inputFormatters: [FilteringTextInputFormatter.allow(RegExp('[0-9.,]')),],
onChanged: (value) => doubleVar = double.parse(value),

RegExp('[0-9.，]')允许0到9之间的数字，也允许逗号和点。

double.parse()将字符串转换为double。

别忘了你需要: 导入的包:颤振/ services.dart ';

设置你的keyboardType为TextInputType.number，

例如:keyboardType: TextInputType.number，

         TextFormField(
            controller: yourcontroller,
            keyboardType: TextInputType.number,
            decoration: const InputDecoration(
              labelText: 'Mobile',
              suffixIcon: Padding(
                padding: EdgeInsets.only(),
                child:
                Icon(Icons.phone_outlined, color: Color(0xffff4876)),
              ),
            ),
            validator: (text) {
              if (text == null || text.isEmpty) {
                return 'Please enter your Mobile No.';
              }
              return null;
            },
          ),

下面是Android上实际的手机键盘代码:

按键部分:keyboardType: TextInputType.phone，

  TextFormField(
    style: TextStyle(
      fontSize: 24
    ),
    controller: _phoneNumberController,
    keyboardType: TextInputType.phone,
    decoration: InputDecoration(
      prefixText: "+1 ",
      labelText: 'Phone number'),
    validator: (String value) {
      if (value.isEmpty) {
        return 'Phone number (+x xxx-xxx-xxxx)';
      }
      return null;
    },
  ),

你需要加一条线

keyboardType: TextInputType.phone,

在块“TextFormField”。在下面的例子:

TextField(
  controller: _controller,
  keyboardType: TextInputType.phone,
),

它应该是这样的:

设置键盘和验证器

String numberValidator(String value) {
  if(value == null) {
    return null;
  }
  final n = num.tryParse(value);
  if(n == null) {
    return '"$value" is not a valid number';
  }
  return null;
}

new TextFormField(
    keyboardType: TextInputType.number, 
    validator: numberValidator, 
    textAlign: TextAlign.right
    ...

https://docs.flutter.io/flutter/material/TextFormField/TextFormField.html https://docs.flutter.io/flutter/services/TextInputType-class.html