通过flutter中的项目总数显示每个列表项的数量(计数)
Show the number(count) of each list item by the total number of items in flutter
我想将列表中每个项目的编号显示到卡片中,我找到了一些示例,他们说您应该使用 for() 循环来完成,我就是这样做的,但是编号不是根本没有增加有人能告诉我我做错了什么吗?
我的代码:
child: ScrollablePositionedList.builder(
itemScrollController: itemController,
itemCount: selectedChallenge.contestantsList.length,
shrinkWrap: true,
itemBuilder: (context, index) {
final sortedList = selectedChallenge.contestantsList
..sort((itemOne, itemTwo) =>
itemTwo.points.compareTo(itemOne.points));
final data = sortedList[index];
// My for loop
for (var i = 0;
i < selectedChallenge.contestantsList.length;
i++,) {
return Card(
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Row(
children: [
Padding(
padding: const EdgeInsets.all(10.0),
child: Text('${i}'),
),
SizedBox(
height: 35,
width: 35,
child: CachedNetworkImage(
imageUrl: data.avatar,
),
),
SizedBox(
width: 12,
),
Text(
data.firstName + ' ' + data.lastName,
),
],
),
Text(data.points.toString()),
],
),
);
}
},
),
我得到了什么:
我想要的:
]
使用构建器的索引并删除 for 循环
ScrollablePositionedList.builder(
itemScrollController: itemController,
itemCount: selectedChallenge.contestantsList.length,
shrinkWrap: true,
itemBuilder: (context, index) {
final sortedList = selectedChallenge.contestantsList
..sort((itemOne, itemTwo) =>
itemTwo.points.compareTo(itemOne.points));
final data = sortedList[index];
return Card(
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Row(
children: [
Padding(
padding: const EdgeInsets.all(10.0),
child: Text('${index + 1}'),
),
// rest of the code
另一个建议是先对列表进行排序,然后再构建它。
// sort the list first in a method or something
final sortedList = selectedChallenge.contestantsList
..sort((itemOne, itemTwo) =>
itemTwo.points.compareTo(itemOne.points));
// build it
ScrollablePositionedList.builder(
itemScrollController: itemController,
itemCount: sortedList.length,
试试下面的代码希望对你有帮助。
声明一个整型变量
int index = 1;
您的小部件。
Text(
(index + 1).toString(),
),
整个小部件。
SingleChildScrollView(
child: Column(
children: <Widget>[
Row(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.center,
children: [
Padding(
padding: const EdgeInsetsDirectional.only(
top: 18, bottom: 18),
child: Text("Powered By:",
style: new TextStyle(fontSize: 18.0)),
)
],
),
ListView.builder(
padding: EdgeInsets.zero,
shrinkWrap: true,
physics: NeverScrollableScrollPhysics(),
itemCount: 10,
itemBuilder: (BuildContext context, int index) {
return Card(
margin: EdgeInsets.zero,
elevation: 0.4,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(0),
),
child: Container(
child: ListTile(
leading: Expanded(
child: Text(
(index + 1).toString(),
),
),
title: Text(
"Coconut Oil",
style: TextStyle(
color: Colors.black87,
fontWeight: FontWeight.bold),
),
subtitle: Row(
children: <Widget>[
Icon(Icons.linear_scale,
color: Colors.greenAccent),
Text("Go Green!",
style: TextStyle(
color: Colors.black87))
],
),
)));
})
],
),
),
你的结果屏幕像->
我想将列表中每个项目的编号显示到卡片中,我找到了一些示例,他们说您应该使用 for() 循环来完成,我就是这样做的,但是编号不是根本没有增加有人能告诉我我做错了什么吗?
我的代码:
child: ScrollablePositionedList.builder(
itemScrollController: itemController,
itemCount: selectedChallenge.contestantsList.length,
shrinkWrap: true,
itemBuilder: (context, index) {
final sortedList = selectedChallenge.contestantsList
..sort((itemOne, itemTwo) =>
itemTwo.points.compareTo(itemOne.points));
final data = sortedList[index];
// My for loop
for (var i = 0;
i < selectedChallenge.contestantsList.length;
i++,) {
return Card(
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Row(
children: [
Padding(
padding: const EdgeInsets.all(10.0),
child: Text('${i}'),
),
SizedBox(
height: 35,
width: 35,
child: CachedNetworkImage(
imageUrl: data.avatar,
),
),
SizedBox(
width: 12,
),
Text(
data.firstName + ' ' + data.lastName,
),
],
),
Text(data.points.toString()),
],
),
);
}
},
),
我得到了什么:
我想要的:
]
使用构建器的索引并删除 for 循环
ScrollablePositionedList.builder(
itemScrollController: itemController,
itemCount: selectedChallenge.contestantsList.length,
shrinkWrap: true,
itemBuilder: (context, index) {
final sortedList = selectedChallenge.contestantsList
..sort((itemOne, itemTwo) =>
itemTwo.points.compareTo(itemOne.points));
final data = sortedList[index];
return Card(
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Row(
children: [
Padding(
padding: const EdgeInsets.all(10.0),
child: Text('${index + 1}'),
),
// rest of the code
另一个建议是先对列表进行排序,然后再构建它。
// sort the list first in a method or something
final sortedList = selectedChallenge.contestantsList
..sort((itemOne, itemTwo) =>
itemTwo.points.compareTo(itemOne.points));
// build it
ScrollablePositionedList.builder(
itemScrollController: itemController,
itemCount: sortedList.length,
试试下面的代码希望对你有帮助。
声明一个整型变量
int index = 1;
您的小部件。
Text(
(index + 1).toString(),
),
整个小部件。
SingleChildScrollView(
child: Column(
children: <Widget>[
Row(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.center,
children: [
Padding(
padding: const EdgeInsetsDirectional.only(
top: 18, bottom: 18),
child: Text("Powered By:",
style: new TextStyle(fontSize: 18.0)),
)
],
),
ListView.builder(
padding: EdgeInsets.zero,
shrinkWrap: true,
physics: NeverScrollableScrollPhysics(),
itemCount: 10,
itemBuilder: (BuildContext context, int index) {
return Card(
margin: EdgeInsets.zero,
elevation: 0.4,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(0),
),
child: Container(
child: ListTile(
leading: Expanded(
child: Text(
(index + 1).toString(),
),
),
title: Text(
"Coconut Oil",
style: TextStyle(
color: Colors.black87,
fontWeight: FontWeight.bold),
),
subtitle: Row(
children: <Widget>[
Icon(Icons.linear_scale,
color: Colors.greenAccent),
Text("Go Green!",
style: TextStyle(
color: Colors.black87))
],
),
)));
})
],
),
),
你的结果屏幕像->