Pass the position of a ListView Element's CheckBox to onChanged callback in Flutter

Question

I wrote the peace of code below:

int numberLines = 50;
List<bool> checkBoxValues = [];

int i = 0;
while(i < numberLines)
{
    checkBoxValues.add(false);
    i++;
}

void medCheckedChanged(bool value) => setState(() => checkBoxValues[position] = value);

ListView.builder
(
    itemCount: numberLines,
    itemBuilder: (context, position)
    {
        return Column
        (
            children: <Widget>
            [
                Container
                (
                    height: resLayout.getScreenHeightPercentage(context, 6),
                    width: resLayout.getScreenHeightPercentage(context, 14),
                    alignment: Alignment(0, 0),
                    child: Checkbox
                    (
                        value: checkBoxValues[position],
                        onChanged: medCheckedChanged,   //pass to medCheckedChanged() the position
                    ),
                )
            ]
        ),
    }
)

As you can see, I need to use the position variable in my medCheckedChanged(bool value) callback, but I can't pass it as a parameter.... Is there any other way to do it?

Thanks in advance and Keep Coding with <3

Solution

Solution: Anonymous Functions

In Dart, you can create one line functions and you can pass parameters to them. Hope this works!

int numberLines = 50;
List<bool> checkBoxValues = [];

int i = 0;
while(i < numberLines)
{
    checkBoxValues.add(false);
    i++;
}

void medCheckedChanged(bool value) => setState(() => checkBoxValues[position] = value);

ListView.builder
(
    itemCount: numberLines,
    itemBuilder: (context, position)
    {
        return Column
        (
            children: <Widget>
            [
                Container
                (
                    height: resLayout.getScreenHeightPercentage(context, 6),
                    width: resLayout.getScreenHeightPercentage(context, 14),
                    alignment: Alignment(0, 0),
                    child: Checkbox
                    (
                        value: checkBoxValues[position],
                        onChanged: (value) => medCheckedChanged(value),   //pass to medCheckedChanged() the position
                    ),
                )
            ]
        ),
    }
)

Comments

[Golden Lion]

A better way is to pass the object associated with the list view contents. You can then reposition your list view to the selected object.

[Golden Lion]

void medCheckedChanged(bool value) => setState(() => checkBoxValues[position] = value); this code looks incorrect. position should be throwing an error since it was not passed to the void function

[sal65535]

Thanks for your answer