Flutter——数组以符号隔开转字符串

///数组转字符串
String getTaskScreen(List list){
    List tempList =List();
    String str = '';
    list.forEach((f){
      tempList.add(f.title);
    });

    tempList.forEach((f){
      if(str == ''){
        str = "$f";
      }else{
        str = "$str"",""$f";
      }
    });

    returnstr;
  }