How to display widgets in a specific pattern dynamically in Flutter?

Question

I want to display widget in a specific pattern. I try to use GridView, but it seems that GridView can only set one value at crossAxisCount. I want it to be 3, 2 pattern. I have refer to @chunhunghan answer at this, but the pattern is in 00, 111, 22, 333, 44, 555 pattern vertically. I want it to be 012, 34, 567, 89 pattern vertically. I have attached the expected output. Thank you.

 GridView.builder(
      gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
          crossAxisCount: 3, childAspectRatio: 1),
      itemCount: 10,
      itemBuilder: (context, index) {
        return Column(children: <Widget>[
          Icon(Icons.access_alarm,
              color: Colors.redAccent, size: 100.0),
          Text(index.toString())
        ],);
      })

Output Expected Output

Naveen Avidi · Accepted Answer · 2020-01-10 04:58:07Z

3

modify the below code as per your requirement ! UPDATED

    int itemCount = 100, lastCount = 3, lastNum = 0;

@override
  void initState(){
    super.initState();
    itemCount++;
  }

      @override
      Widget build(BuildContext context) {
        return ListView.builder(
            itemCount: ((itemCount / 3 / 2) + (itemCount / 2 / 2)).toInt(),
            itemBuilder: (con, ind) {
              if (lastCount == 3) {
                lastCount = 2;

                //Add below condition to show exact pattern by avoiding extra numbers
                return (itemCount - lastNum) >= lastCount + 1
                    ? Row(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: List.generate(lastCount + 1, (cInd) {
                          lastNum++;

                          //Below condition to show upto itemCount by showing remaining numbers in next line ! It won't work if you use above formula. i.e Showing Exact Pattern
                          return lastNum < itemCount + 2
                              ? Column(mainAxisSize: MainAxisSize.min, children: [
                                  Icon(Icons.check_circle),
                                  Text('${lastNum - 1}')
                                ])
                              : SizedBox();
                        }))
                    : SizedBox();
              } else {
                lastCount = 3;

                //Add below condition to show exact pattern by avoiding extra numbers
                return (itemCount - lastNum) >= lastCount - 1
                    ? Row(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: List.generate(lastCount - 1, (cInd) {
                          lastNum++;

                          //Below condition to show upto itemCount by showing remaining numbers in next line ! It won't work if you use above formula. i.e Showing Exact Pattern
                          return lastNum < itemCount + 2
                              ? Column(mainAxisSize: MainAxisSize.min, children: [
                                  Icon(Icons.check_circle),
                                  Text('${lastNum - 1}')
                                ])
                              : SizedBox();
                        }))
                    : SizedBox();
              }
            });
      }

edited Jan 10, 2020 at 4:58

answered Jan 9, 2020 at 9:35

Naveen Avidi

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9 Comments

Nur Haslina Over a year ago

Thank you @Naveen Avidi! I will try to run the codes and get back to you.

Naveen Avidi Over a year ago

Ok let me know ! I tested on dart pad !

Nur Haslina Over a year ago

Hi @Naveen Avidi! I have run the codes. It works dynamically on larger itemCount. Thank you very much for your help!

Nur Haslina Over a year ago

But, I have issues when I change the itemCount to numbers that is not in multiple of 5. I guess the above code only suitable for itemCount that is multiple of 5?

Naveen Avidi Over a year ago

You have to change this line according to pattern==> itemCount: ((itemCount / 3 / 2) + (itemCount / 2 / 2)).toInt(),

|

Oliver Atienza · Accepted Answer · 2020-01-09 03:42:03Z

0

Maybe you could just "pad" the rows with only 2 items with an empty Container() if that workaround works for you?

GridView.builder(
      gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
          crossAxisCount: 3, childAspectRatio: 1),
      itemCount: 10,
      itemBuilder: (context, index) {
        return Column(children: <Widget>[
          Icon(Icons.access_alarm,
              color: Colors.redAccent, size: 100.0),
          Text(index.toString()),
          Container()
        ],);
      })

or check if the index is odd or even then have two builder functions, one return 3 items and the other returning only 2

answered Jan 9, 2020 at 3:42

Oliver Atienza

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1 Comment

Brett Pontarelli Over a year ago

in your answer the empty container() is in the item so that would just add space (and maybe 0 space I'm not certain) to the bottom of each icon and number item. How do you get padding (and the right size padding) to both the left and right of each row of clocks?

Brett Pontarelli · Accepted Answer · 2020-01-09 03:55:23Z

0

Keep things simple and just use Row and Column with MainAxisAlignment.center. Here is a working DartPad and the code:

  itemBuilder(index) {
    return Column(children: [
      Icon(Icons.access_alarm, color: Colors.redAccent, size: 100.0),
      Text(index.toString())
    ]);
  }

  rowBuilder(start, end) {
    var length = end - start + 1;
    var itemArray = new List<Widget>(length);

    for (var index = 0; index < length; index++) {
      itemArray[index] = itemBuilder(start + index);
    }

    return Row(
        mainAxisAlignment: MainAxisAlignment.center, children: itemArray);
  }

  @override
  Widget build(BuildContext context) {
    return Column(children: [
      rowBuilder(0, 2),
      rowBuilder(3, 4),
      rowBuilder(5, 7),
      rowBuilder(8, 9),
    ]);
  }

answered Jan 9, 2020 at 3:55

Brett Pontarelli

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2 Comments

Nur Haslina Over a year ago

Thank you @Brett Pontarelli! Actually, I want to use GridView because I want it to be dynamic. The solution that you suggest achieve the expected output. But how to make it dynamic without need to specify rowBuilder(0, 2), rowBuilder(3, 4), rowBuilder(5, 7), rowBuilder(8, 9)?

Nur Haslina Over a year ago

Let say the length of the item is 100, I don't want to specify manually the rowBuilder. I want it to be dynamic. Can you help me? I spend 2 weeks to find solution on this matter. Thank you.

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