How to get deselected item from the selected item on flutter?-CodePudding

I built multi select chips using Map function. And when selected a chip then color change to yellow. When selected chips then print selected chips. Like that I want to select chips and display the unselected chips out of them.

code

 List<String> hobbyList = [
    'Shopping',
    'Brunch',
    'Music',
    'Road Trips',
    'Tea',
    'Trivia',
    'Comedy',
    'Clubbing',
    'Drinking',
    'Wine',
  ];

  List<String>? selectedHobby = [];

Column(
                        children: <Widget>[
                          const SizedBox(height: 16),
                          Wrap(
                            children: hobbyList.map(
                              (hobby) {
                                bool isSelected = false;
                                if (selectedHobby!.contains(hobby)) {
                                  isSelected = true;
                                }
                                return GestureDetector(
                                  onTap: () {
                                    if (!selectedHobby!.contains(hobby)) {
                                      if (selectedHobby!.length < 50) {
                                        selectedHobby!.add(hobby);
                                        setState(() {});
                                        print(selectedHobby);
                                      }
                                    } else {
                                      selectedHobby!.removeWhere(
                                          (element) => element == hobby);
                                      setState(() {});
                                      print(selectedHobby);
                                    }
                                  },
                                  child: Container(
                                    margin: const EdgeInsets.symmetric(
                                        horizontal: 5, vertical: 4),
                                    child: Container(
                                      padding: const EdgeInsets.symmetric(
                                          vertical: 5, horizontal: 12),
                                      decoration: BoxDecoration(
                                          color: isSelected
                                              ? HexColor('#F5F185')
                                              : HexColor('#D9D9D9'),
                                          borderRadius:
                                              BorderRadius.circular(18),
                                          border: Border.all(
                                              color: isSelected
                                                  ? HexColor('#F5F185')
                                                  : HexColor('#D9D9D9'),
                                              width: 2)),
                                      child: Text(
                                        hobby,
                                        style: TextStyle(
                                            color: isSelected
                                                ? Colors.black
                                                : Colors.black,
                                            fontSize: 14,
                                            fontWeight: FontWeight.w600),
                                      ),
                                    ),
                                  ),
                                );
                              },
                            ).toList(),
                          ),
                        ],
                      ),

EX: first all user select "shopping" , "brunch" and "music" then print that in console and color change to yellow like this.. console..

Now user unselected the "music" and "brunch" items .. UI

console

**Now selected item is only "shopping", that's display perfectly as I mention on the top. Like that is want display unselected list separately.

ex:

unselectedList :- [ brunch , music]**

CodePudding user response：

Create One more list like this :

  List<String>? deSelectedHobby = [];

And Update it when use deselects any item :

                               onTap: () {
                                    if (!selectedHobby!.contains(hobby)) {
                                      if (selectedHobby!.length < 50) {
                                        selectedHobby!.add(hobby);
                                        deSelectedHobby!.removeWhere(
                                          (element) => element == hobby);
                                        setState(() {});
                                        print(selectedHobby);
                                      }
                                    } else {
                                      selectedHobby!.removeWhere(
                                          (element) => element == hobby);
                                      deSelectedHobby!.add(hobby);
                                      setState(() {});
                                      print(selectedHobby);
                                    }
                                  },