Null checker null safety error how i can stopped it

Question

I'm designing a mobile Application ,it looks like "WhatsApp" I initiate class called "chat model"

when i run app it gives me "Null safety error or null checker" I want to display the name of person

please advice me to solve this problem

 class Chat Model {     */my code in chat model class
  String? name;
  String? icon;  
  bool? is group;
  String? time;
  String? current message;
  Chat Model(
  {this.name, this. icon, this.is group, this. time, this. current message});
}


     


       class chatpage extends StatefulWidget {  */ my code in chat page 
       const chatpage({super.key});

        @override
      State<chatpage> createState() => _chatpageState();
  }

  // ignore: camel_case_types
  class _chatpageState extends State<chatpage> {
   List<ChatModel> chats = [
    ChatModel(
    name: "Ahmed omar",
    icon: "person.svg",
    isgroup: false,
    time: "10:00",
    currentmessage: "Hi Ahmed"),
    ChatModel(
    name: "Hussien Mohamed",
    icon: "person.svg",
    isgroup: true,
    time: "10:00",
    currentmessage: "Hi everyone"),
    ChatModel(
    name: "Hussien omar",
    icon: "person.svg",
    isgroup: false,
    time: "10:00",
    currentmessage: "Hi Hussien"),
    ChatModel(
    name: "Hussien omar",
     icon: "person.svg",
     isgroup: true,
     time: "10:00",
     currentmessage: "Hi everyone"),
      ];
           
                                  */ error here

                  Text(
                    widget.chatModel!.name,
                    style: TextStyle(
                      fontSize: 18.5,
                      fontWeight: FontWeight.bold,
                    ),