颤动的颜色不会随着索引的变化而改变 [英] Flutter color not chaning on change of index

问题描述

我想更改容器水龙头上的颜色.所以我只是为了让循环显示容器并在索引相同时更改颜色.但是问题是索引在变化，但是颜色没有变化.我已经检查了currentIndex的打印值是否发生了变化，但是我不知道为什么颜色没有发生变化我正在使用有状态的小部件

I want to change the color on the tap of the container. So I just for loop to show container and change color when index is the same. But the issue is index is changing but the color is not. I have checked by the print value of currentIndex is changing but don't know why the color isn't changing I am using a stateful widget

代码

List categories = [
  {'CatID': 0, 'CatName': 'All'},
  {'CatID': 1, 'CatName': 'Computer Hardware'},
  {'CatID': 2, 'CatName': 'Computer Software'},
  {'CatID': 3, 'CatName': 'Internet'},
  {'CatID': 4, 'CatName': 'Windows Installation'},
];

List<Widget> CatWidget = List<Widget>(); // Here we defined a list of widget!


class ShopScreen extends StatefulWidget {
  @override
  _ShopScreenState createState() => _ShopScreenState();
}

class _ShopScreenState extends State<ShopScreen> {
  int currentindex = 0;

  @override
  Widget build(BuildContext context) {
    double statusBarHeight = MediaQuery.of(context).padding.top;
    double Height = MediaQuery.of(context).size.height;
    double Width = MediaQuery.of(context).size.width;

    for (int i = 0; i < categories.length; i++) {
      CatWidget.add(
        GestureDetector(
          onTap: () {
            setState(() {
              // set current index!
              currentindex = i;
              print(currentindex);
            });
          },
          child: Container(
            child: Padding(
              padding: const EdgeInsets.only(left: 10),
              child: Container(
                height: Height * 0.04,
                decoration: BoxDecoration(
                    color: currentindex == i
                        ? Color(0xff04385f)
                        : Colors.white, // Here we checked!,
                    border: Border.all(color: Colors.grey[300]),
                    borderRadius: BorderRadius.all(Radius.circular(10))),
                child: Center(
                    child: Text(
                  categories[i]['CatName'],
                  style: TextStyle(
                      fontSize: 10,
                      color: currentindex == i ? Colors.white : Colors.grey,
                      fontFamily: 'UbuntuRegular'),
                )),
              ),
            ),
          ),
        ),
      );
    }

推荐答案

像这样更改列表小部件

 final CatWidget = <Widget>[]; 

我已经检查了代码的工作正常，只需像这样定义Widget，然后在Widget Build的for循环上方定义.

I have checked the code its working fine just define the Widget like this and I define just above the for loop in Widget Build.

最终代码如下:

class ShopScreen extends StatefulWidget {
  @override
  _ShopScreenState createState() => _ShopScreenState();
}

class _ShopScreenState extends State<ShopScreen> {
  int currentindex = 0;

  @override
  Widget build(BuildContext context) {
    double statusBarHeight = MediaQuery.of(context).padding.top;
    double Height = MediaQuery.of(context).size.height;
    double Width = MediaQuery.of(context).size.width;

     final CatWidget = <Widget>[]; // Here we defined a list of widget!

    for (int i = 0; i < categories.length; i++) {
      CatWidget.add(
        GestureDetector(
          onTap: () {
            setState(() {
              // set current index!
              currentindex = i;
              print(currentindex);
            });
          },
          child: Container(
            child: Padding(
              padding: const EdgeInsets.only(left: 10),
              child: Container(
                height: Height * 0.04,
                decoration: BoxDecoration(
                    color: currentindex == i
                        ? Color(0xff04385f)
                        : Colors.white, // Here we checked!,
                    border: Border.all(color: Colors.grey[300]),
                    borderRadius: BorderRadius.all(Radius.circular(10))),
                child: Center(
                    child: Text(
                  categories[i]['CatName'],
                  style: TextStyle(
                      fontSize: 10,
                      color: currentindex == i ? Colors.white : Colors.grey,
                      fontFamily: 'UbuntuRegular'),
                )),
              ),
            ),
          ),
        ),
      );
    }

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