Why i used getX not work in flutter ListView?-CodePudding

when I tap containter and update selectedIndex equal current index, but it not will update.

class HomeController extends GetxController {

  final RxList<PurineTypeModel> dataSource = RxList();
  final selectedIndex = 0.obs;
}

Obx(() {
          return ListView.builder(
              cacheExtent: 30,
              scrollDirection: Axis.horizontal,
              itemBuilder: (c, index) {
                print("refresh?? $index");
                return GestureDetector(child: Container(
                  width: 100,
                  color: controller.selectedIndex.value == index ? Colors.red : Colors.green,
                  child: Text(
                      controller.selectedIndex.string),
                ), onTap: () {
                  controller.selectedIndex.value = 1;
                },);
              },
              itemCount: controller.dataSource.length);
        })

CodePudding user response：

onTap: () {
                  controller.selectedIndex.value = index;
                },);

setup index element not 1 the controller is initialized how?

CodePudding user response：

You need to wrap the GestureDetector also in an Obx, so like this:

Obx(() {
  return ListView.builder(
      cacheExtent: 30,
      scrollDirection: Axis.horizontal,
      itemBuilder: (c, index) {
        print("refresh?? $index");
        return Obx(() =>
            GestureDetector(child: Container(
              width: 100,
              color: controller.selectedIndex.value == index ? Colors
                  .red : Colors.green,
              child: Text(
                  controller.selectedIndex.string),
            ), onTap: () {
              controller.selectedIndex.value = 1;
            },));
      },
      itemCount: controller.dataSource.length);
})

Because the outer Obx only observes controller.dataSource.length